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<article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" article-type="research-article" dtd-version="1.4" xml:lang="en">
  <front>
    <journal-meta>
      <journal-id journal-id-type="publisher-id">jamp</journal-id>
      <journal-title-group>
        <journal-title>Journal of Applied Mathematics and Physics</journal-title>
      </journal-title-group>
      <issn pub-type="epub">2327-4379</issn>
      <issn pub-type="ppub">2327-4352</issn>
      <publisher>
        <publisher-name>Scientific Research Publishing</publisher-name>
      </publisher>
    </journal-meta>
    <article-meta>
      <article-id pub-id-type="doi">10.4236/jamp.2026.144061</article-id>
      <article-id pub-id-type="publisher-id">jamp-150613</article-id>
      <article-categories>
        <subj-group>
          <subject>Article</subject>
        </subj-group>
        <subj-group>
          <subject>Physics</subject>
          <subject>Mathematics</subject>
        </subj-group>
      </article-categories>
      <title-group>
        <article-title>Emergent Gravitation and Quantum Wave Dynamics from a Bounded Vacuum</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author" corresp="yes">
          <name name-style="western">
            <surname>Kumar</surname>
            <given-names>Tanuj</given-names>
          </name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Vandana</string-name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
      </contrib-group>
      <aff id="aff1"><label>1</label> Department of Physics and Astronomical Sciences, Central University of Jammu, Jammu, India </aff>
      <author-notes>
        <fn fn-type="conflict" id="fn-conflict">
          <p>The authors declare no conflicts of interest regarding the publication of this paper.</p>
        </fn>
      </author-notes>
      <pub-date pub-type="epub">
        <day>01</day>
        <month>04</month>
        <year>2026</year>
      </pub-date>
      <pub-date pub-type="collection">
        <month>04</month>
        <year>2026</year>
      </pub-date>
      <volume>14</volume>
      <issue>04</issue>
      <fpage>1308</fpage>
      <lpage>1333</lpage>
      <history>
        <date date-type="received">
          <day>19</day>
          <month>02</month>
          <year>2026</year>
        </date>
        <date date-type="accepted">
          <day>31</day>
          <month>03</month>
          <year>2026</year>
        </date>
        <date date-type="published">
          <day>03</day>
          <month>04</month>
          <year>2026</year>
        </date>
      </history>
      <permissions>
        <copyright-statement>© 2026 by the authors and Scientific Research Publishing Inc.</copyright-statement>
        <copyright-year>2026</copyright-year>
        <license license-type="open-access">
          <license-p> This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ( <ext-link ext-link-type="uri" xlink:href="https://creativecommons.org/licenses/by/4.0/">https://creativecommons.org/licenses/by/4.0/</ext-link> ). </license-p>
        </license>
      </permissions>
      <self-uri content-type="doi" xlink:href="https://doi.org/10.4236/jamp.2026.144061">https://doi.org/10.4236/jamp.2026.144061</self-uri>
      <abstract>
        <p>We present a framework in which gravitation, inertia, and wave dynamics emerge from the response of a vacuum endowed with finite potential capacity. The theory is formulated in terms of a scalar vacuum-potential field whose absolute normalization is fixed by relativistic considerations, such that the equilibrium value at infinity equals <inline-formula><mml:math></mml:math></inline-formula></p>
        <p>c</p>
        <p>2</p>
        <p>. Static relaxation of localized vacuum-potential deficits reproduces Newtonian gravity in the coarse-grained limit, while time-dependent redistribution generates propagating disturbances governed by a universal wave equation. Finite vacuum capacity implies intrinsic upper bounds on transmissible force and signal speed, yielding <inline-formula><mml:math></mml:math></inline-formula></p>
        <p>F</p>
        <p>max</p>
        <p>=</p>
        <p>c</p>
        <p>4</p>
        <p>/G</p>
        <p>and <inline-formula><mml:math></mml:math></inline-formula></p>
        <p>v≤c</p>
        <p>without invoking spacetime geometry or independent kinematic postulates. Vacuum microstructure further leads to a universal lattice dispersion relation with Planck-suppressed corrections, <inline-formula><mml:math></mml:math></inline-formula></p>
        <p>Δv</p>
        <p>c</p>
        <p>≃−</p>
        <p>1</p>
        <p>8</p>
        <p>(</p>
        <p>E</p>
        <p>E</p>
        <p>P</p>
        <p>)</p>
        <p>2</p>
        <p>, consistent with current astrophysical and gravitational-wave constraints. Gravitational redshift, lensing, horizons, and quantum correlations arise as energetic consequences of bounded vacuum response. The vacuum is modelled as a Dynamical Planck Network (DPN), providing a conservative and internally consistent bridge between relativistic gravitation and quantum wave phenomena.</p>
      </abstract>
      <kwd-group kwd-group-type="author-generated" xml:lang="en">
        <kwd>Vacuum</kwd>
        <kwd>Gravitation</kwd>
        <kwd>Wave Dynamics</kwd>
        <kwd>Compton Length</kwd>
        <kwd>Dispersion</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec1">
      <title>1. Section I—Introduction</title>
      <p>Understanding the physical origin of gravitation, inertia, and quantum wave phenomena remains one of the central challenges of fundamental physics. The general theory of relativity successfully describes gravity as the geometry of spacetime, while quantum theory governs matter and radiation through wave dynamics and discrete action. Despite their empirical success, these frameworks rely on conceptually distinct foundations, and a common microscopic origin for gravitational and quantum phenomena has yet to be established [<xref ref-type="bibr" rid="B1">1</xref>]-[<xref ref-type="bibr" rid="B3">3</xref>].</p>
      <p>A recurring theme in attempts to bridge this gap is the idea that spacetime or the vacuum itself may possess an underlying structure with finite response capacity. Horizon thermodynamics, maximum-force arguments, and emergent-gravity approaches all point toward the existence of universal bounds—on force, tension, and signal propagation—that appear independent of detailed dynamics [<xref ref-type="bibr" rid="B4">4</xref>]-[<xref ref-type="bibr" rid="B7">7</xref>]. At the same time, lattice field theory and condensed-matter analogs demonstrate that wave propagation, dispersion, and effective geometry can arise from collective responses of discrete or capacity-limited media without assuming spacetime geometry a priori [<xref ref-type="bibr" rid="B8">8</xref>]-[<xref ref-type="bibr" rid="B10">10</xref>]. In general relativity, energy—not force—is the fundamental invariant, and the potential at spatial infinity is fixed by the requirement that clocks recover special-relativistic behavior far from gravitating sources [<xref ref-type="bibr" rid="B11">11</xref>]-[<xref ref-type="bibr" rid="B13">13</xref>]. This suggests that gravitational phenomena may be understood, at least in part, as consequences of spatial and temporal variations of a bounded vacuum-potential field rather than as primary geometric axioms.</p>
      <p>Motivated by these observations, we introduce a framework in which gravitation, inertia, and wave dynamics emerge from the response of a vacuum endowed with finite, bounded potential capacity. The central object of the theory is a scalar vacuum-potential field <inline-formula><mml:math><mml:mtext> Φ </mml:mtext></mml:math></inline-formula> , normalized such that <inline-formula><mml:math><mml:mrow><mml:msub><mml:mtext> Φ </mml:mtext><mml:mi> ∞ </mml:mi></mml:msub><mml:mo> = </mml:mo><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:math></inline-formula> , whose variations encode both static and dynamical physical effects. No spacetime geometry, force laws, or canonical quantization are assumed a priori. Instead, gravitational attraction arises from static relaxation of localized vacuum-potential deficits, while wave propagation corresponds to time-dependent redistribution of the same field.</p>
      <p>Within this approach, universal bounds on force, tension, and signal speed emerge naturally from the finite transmissibility of the vacuum. Horizons and black-hole-like behavior appear as limiting cases of vacuum-capacity saturation rather than as fundamental singularities, and Planck-scale corrections to wave propagation follow from the underlying vacuum response. Quantum correlations are interpreted as global constraints on vacuum configurations, consistent with relativistic causality.</p>
      <p>The purpose of this paper is to develop the bounded-vacuum framework in a controlled and conservative manner. Section II establishes the relativistic normalization of the vacuum potential and its continuum representation. Sections III-V derive gravitational response, inertial effects, and universal force bounds from finite vacuum capacity. Sections VI-VIII analyze wave dynamics, dispersion, and observational consistency. The physical implications—including horizons, redshift, lensing, and quantum correlations—are summarized in later sections. Throughout, we emphasize that geometry, quantization, and relativistic structure emerge as effective descriptions of an underlying vacuum response rather than as independent postulates.</p>
    </sec>
    <sec id="sec2">
      <title>2. Section II—Vacuum Potential Field and Relativistic Normalization</title>
      <p>This section establishes the continuum foundation of the bounded-vacuum framework. We introduce a scalar vacuum-potential field <inline-formula><mml:math><mml:mrow><mml:mtext> Φ </mml:mtext><mml:mrow><mml:mo> ( </mml:mo><mml:mi> x </mml:mi><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> , defined as energy per unit mass, fix its absolute normalization using the theory of relativity, and formulate the notion of a self-consistent vacuum deficit. No assumptions regarding force laws, wave propagation, or microscopic discreteness are introduced at this stage; these features emerge in subsequent sections from the dynamical response of the bounded vacuum.</p>
      <sec id="sec2dot1">
        <title>2.1. Vacuum Potential as Energy per Unit Mass</title>
        <p>We describe the vacuum by a scalar field <inline-formula><mml:math><mml:mrow><mml:mtext> Φ </mml:mtext><mml:mrow><mml:mo> ( </mml:mo><mml:mi> x </mml:mi><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> with dimensions of energy per unit mass. In relativistic physics, the invariant relation between mass and energy is expressed through the rest-energy formula [<xref ref-type="bibr" rid="B1">1</xref>][<xref ref-type="bibr" rid="B2">2</xref>].</p>
        <p>For a particle of inertial (test) mass <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> m </mml:mi><mml:mi> t </mml:mi></mml:msub></mml:mrow></mml:math></inline-formula> , special relativity gives</p>
        <disp-formula id="FD1">
          <label>(2.1)</label>
          <mml:math>
            <mml:mrow>
              <mml:msub>
                <mml:mi>E</mml:mi>
                <mml:mn>0</mml:mn>
              </mml:msub>
              <mml:mo>=</mml:mo>
              <mml:msub>
                <mml:mi>m</mml:mi>
                <mml:mi>t</mml:mi>
              </mml:msub>
              <mml:msup>
                <mml:mi>c</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>Equation (2.1) identifies <inline-formula><mml:math><mml:mrow><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:math></inline-formula> as the universal energy-per-mass scale associated with flat spacetime [<xref ref-type="bibr" rid="B1">1</xref>][<xref ref-type="bibr" rid="B2">2</xref>][<xref ref-type="bibr" rid="B14">14</xref>]. Motivated by this relation, we take the reference value of the vacuum potential in the absence of gravitational loading to be</p>
        <disp-formula id="FD2">
          <mml:math>
            <mml:mrow>
              <mml:msub>
                <mml:mtext>Φ</mml:mtext>
                <mml:mn>0</mml:mn>
              </mml:msub>
              <mml:mo>=</mml:mo>
              <mml:msup>
                <mml:mi>c</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>Physical gravitational or inertial effects are then described by deviations of <inline-formula><mml:math><mml:mrow><mml:mtext> Φ </mml:mtext><mml:mrow><mml:mo> ( </mml:mo><mml:mi> x </mml:mi><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> from this baseline.</p>
      </sec>
      <sec id="sec2dot2">
        <title>2.2. Relativistic Fixing of the Vacuum Reference Level</title>
        <p>In Newtonian gravity, the potential is defined only up to an additive constant. In contrast, general relativity fixes the absolute normalization of energy through spacetime geometry [<xref ref-type="bibr" rid="B1">1</xref>][<xref ref-type="bibr" rid="B2">2</xref>].</p>
        <p>For a static weak gravitational field generated by a localized source, the Schwarzschild metric yields, to leading order [<xref ref-type="bibr" rid="B2">2</xref>][<xref ref-type="bibr" rid="B15">15</xref>]-[<xref ref-type="bibr" rid="B18">18</xref>],</p>
        <disp-formula id="FD3">
          <label>(2.2)</label>
          <mml:math display="inline">
            <mml:mrow>
              <mml:msub>
                <mml:mi>g</mml:mi>
                <mml:mrow>
                  <mml:mn>00</mml:mn>
                </mml:mrow>
              </mml:msub>
              <mml:mo>≃</mml:mo>
              <mml:mo>−</mml:mo>
              <mml:mrow>
                <mml:mo>(</mml:mo>
                <mml:mrow>
                  <mml:mn>1</mml:mn>
                  <mml:mo>+</mml:mo>
                  <mml:mfrac>
                    <mml:mrow>
                      <mml:mn>2</mml:mn>
                      <mml:msub>
                        <mml:mtext>Φ</mml:mtext>
                        <mml:mi>N</mml:mi>
                      </mml:msub>
                    </mml:mrow>
                    <mml:mrow>
                      <mml:msup>
                        <mml:mi>c</mml:mi>
                        <mml:mn>2</mml:mn>
                      </mml:msup>
                    </mml:mrow>
                  </mml:mfrac>
                </mml:mrow>
                <mml:mo>)</mml:mo>
              </mml:mrow>
              <mml:mo>,</mml:mo>
              <mml:mrow>
                <mml:mo>|</mml:mo>
                <mml:mrow>
                  <mml:msub>
                    <mml:mtext>Φ</mml:mtext>
                    <mml:mi>N</mml:mi>
                  </mml:msub>
                </mml:mrow>
                <mml:mo>|</mml:mo>
              </mml:mrow>
              <mml:mo>≪</mml:mo>
              <mml:msup>
                <mml:mi>c</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mo>,</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>where <inline-formula><mml:math><mml:mrow><mml:msub><mml:mtext> Φ </mml:mtext><mml:mi> N </mml:mi></mml:msub></mml:mrow></mml:math></inline-formula> denotes the Newtonian gravitational potential.</p>
        <p>The total energy of a particle of test mass <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> m </mml:mi><mml:mi> t </mml:mi></mml:msub></mml:mrow></mml:math></inline-formula> at rest in this spacetime is [<xref ref-type="bibr" rid="B16">16</xref>][<xref ref-type="bibr" rid="B18">18</xref>]</p>
        <disp-formula id="FD4">
          <label>(2.3)</label>
          <mml:math>
            <mml:mrow>
              <mml:mi>E</mml:mi>
              <mml:mo>=</mml:mo>
              <mml:msub>
                <mml:mi>m</mml:mi>
                <mml:mi>t</mml:mi>
              </mml:msub>
              <mml:msup>
                <mml:mi>c</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:msqrt>
                <mml:mrow>
                  <mml:mo>−</mml:mo>
                  <mml:msub>
                    <mml:mi>g</mml:mi>
                    <mml:mrow>
                      <mml:mn>00</mml:mn>
                    </mml:mrow>
                  </mml:msub>
                </mml:mrow>
              </mml:msqrt>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>Expanding Equation (2.3) using Equation (2.2) in the weak-field limit gives</p>
        <disp-formula id="FD5">
          <label>(2.4)</label>
          <mml:math>
            <mml:mrow>
              <mml:mi>E</mml:mi>
              <mml:mo>≃</mml:mo>
              <mml:msub>
                <mml:mi>m</mml:mi>
                <mml:mi>t</mml:mi>
              </mml:msub>
              <mml:msup>
                <mml:mi>c</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mo>+</mml:mo>
              <mml:msub>
                <mml:mi>m</mml:mi>
                <mml:mi>t</mml:mi>
              </mml:msub>
              <mml:msub>
                <mml:mtext>Φ</mml:mtext>
                <mml:mi>N</mml:mi>
              </mml:msub>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>Defining the total potential as energy per unit test mass,</p>
        <disp-formula id="FD6">
          <label>(2.5)</label>
          <mml:math>
            <mml:mrow>
              <mml:msub>
                <mml:mtext>Φ</mml:mtext>
                <mml:mrow>
                  <mml:mtext>tot</mml:mtext>
                </mml:mrow>
              </mml:msub>
              <mml:mo>≡</mml:mo>
              <mml:mfrac>
                <mml:mi>E</mml:mi>
                <mml:mrow>
                  <mml:msub>
                    <mml:mi>m</mml:mi>
                    <mml:mi>t</mml:mi>
                  </mml:msub>
                </mml:mrow>
              </mml:mfrac>
              <mml:mo>,</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>we obtain</p>
        <disp-formula id="FD7">
          <label>(2.6)</label>
          <mml:math>
            <mml:mrow>
              <mml:msub>
                <mml:mtext>Φ</mml:mtext>
                <mml:mrow>
                  <mml:mtext>tot</mml:mtext>
                </mml:mrow>
              </mml:msub>
              <mml:mrow>
                <mml:mo>(</mml:mo>
                <mml:mi>r</mml:mi>
                <mml:mo>)</mml:mo>
              </mml:mrow>
              <mml:mo>=</mml:mo>
              <mml:msup>
                <mml:mi>c</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mo>+</mml:mo>
              <mml:msub>
                <mml:mtext>Φ</mml:mtext>
                <mml:mi>N</mml:mi>
              </mml:msub>
              <mml:mrow>
                <mml:mo>(</mml:mo>
                <mml:mi>r</mml:mi>
                <mml:mo>)</mml:mo>
              </mml:mrow>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>Equation (2.6) shows that relativistic energy normalization naturally decomposes into:</p>
        <p>a universal relativistic baseline <inline-formula><mml:math><mml:mrow><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:math></inline-formula> , anda deviation <inline-formula><mml:math><mml:mrow><mml:msub><mml:mtext> Φ </mml:mtext><mml:mi> N </mml:mi></mml:msub></mml:mrow></mml:math></inline-formula> determined by gravitational sources.</p>
        <p>Thus <inline-formula><mml:math><mml:mrow><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:math></inline-formula> is not an arbitrary additive constant; it is fixed by asymptotic Minkowski normalization [<xref ref-type="bibr" rid="B2">2</xref>][<xref ref-type="bibr" rid="B18">18</xref>].</p>
      </sec>
      <sec id="sec2dot3">
        <title>2.3. Asymptotic Flatness and Uniqueness of the Newtonian Constant</title>
        <p>For a localized gravitating source of mass <inline-formula><mml:math><mml:mi> M </mml:mi></mml:math></inline-formula> , the Newtonian potential takes the form</p>
        <disp-formula id="FD8">
          <label>(2.7)</label>
          <mml:math>
            <mml:mrow>
              <mml:msub>
                <mml:mtext>Φ</mml:mtext>
                <mml:mi>N</mml:mi>
              </mml:msub>
              <mml:mrow>
                <mml:mo>(</mml:mo>
                <mml:mi>r</mml:mi>
                <mml:mo>)</mml:mo>
              </mml:mrow>
              <mml:mo>=</mml:mo>
              <mml:mo>−</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:mi>G</mml:mi>
                  <mml:mi>M</mml:mi>
                </mml:mrow>
                <mml:mi>r</mml:mi>
              </mml:mfrac>
              <mml:mo>+</mml:mo>
              <mml:mi>C</mml:mi>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>Asymptotic flatness requires that spacetime approach Minkowski form as <inline-formula><mml:math><mml:mrow><mml:mi> r </mml:mi><mml:mo> → </mml:mo><mml:mi> ∞ </mml:mi></mml:mrow></mml:math></inline-formula> [<xref ref-type="bibr" rid="B2">2</xref>][<xref ref-type="bibr" rid="B17">17</xref>][<xref ref-type="bibr" rid="B18">18</xref>], implying</p>
        <disp-formula id="FD9">
          <label>(2.8)</label>
          <mml:math display="inline">
            <mml:mrow>
              <mml:msub>
                <mml:mi>g</mml:mi>
                <mml:mrow>
                  <mml:mn>00</mml:mn>
                </mml:mrow>
              </mml:msub>
              <mml:mo>→</mml:mo>
              <mml:mo>−</mml:mo>
              <mml:mn>1</mml:mn>
              <mml:mo>⇔</mml:mo>
              <mml:msub>
                <mml:mi>Φ</mml:mi>
                <mml:mi>N</mml:mi>
              </mml:msub>
              <mml:mrow>
                <mml:mo>(</mml:mo>
                <mml:mi>∞</mml:mi>
                <mml:mo>)</mml:mo>
              </mml:mrow>
              <mml:mo>=</mml:mo>
              <mml:mn>0.</mml:mn>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>This uniquely fixes</p>
        <disp-formula id="FD10">
          <label>(2.9)</label>
          <mml:math>
            <mml:mrow>
              <mml:mi>C</mml:mi>
              <mml:mo>=</mml:mo>
              <mml:mn>0.</mml:mn>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>Hence,</p>
        <disp-formula id="FD11">
          <label>(2.10)</label>
          <mml:math>
            <mml:mrow>
              <mml:msub>
                <mml:mtext>Φ</mml:mtext>
                <mml:mrow>
                  <mml:mtext>tot</mml:mtext>
                </mml:mrow>
              </mml:msub>
              <mml:mrow>
                <mml:mo>(</mml:mo>
                <mml:mi>∞</mml:mi>
                <mml:mo>)</mml:mo>
              </mml:mrow>
              <mml:mo>=</mml:mo>
              <mml:msup>
                <mml:mi>c</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>The vacuum reference level <inline-formula><mml:math><mml:mrow><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:math></inline-formula> is therefore uniquely fixed by relativistic normalization. The Newtonian potential represents deviations from this baseline [<xref ref-type="bibr" rid="B2">2</xref>][<xref ref-type="bibr" rid="B18">18</xref>].</p>
      </sec>
      <sec id="sec2dot4">
        <title>2.4. From External Sources to Self-Consistent Vacuum Deficits</title>
        <p>Equations (2.7)-(2.10) are traditionally derived for a physical gravitating source of mass <inline-formula><mml:math><mml:mi> M </mml:mi></mml:math></inline-formula> . In this framework, however, the same coarse-grained potential form is employed more generally to represent a localized vacuum-potential deficit, irrespective of whether it originates from conventional material matter.</p>
        <p>Accordingly, we introduce a parameter <inline-formula><mml:math><mml:mi> m </mml:mi></mml:math></inline-formula> , characterizing the total integrated vacuum deficit of a localized configuration. For a static, spherically symmetric configuration, the vacuum potential depends only on the radial coordinate <inline-formula><mml:math><mml:mrow><mml:mi> r </mml:mi><mml:mo> = </mml:mo><mml:mrow><mml:mo> | </mml:mo><mml:mi> x </mml:mi><mml:mo> | </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> . Replacing <inline-formula><mml:math><mml:mrow><mml:mi> M </mml:mi><mml:mo> → </mml:mo><mml:mi> m </mml:mi></mml:mrow></mml:math></inline-formula> , the continuum vacuum-potential profile is written</p>
        <disp-formula id="FD12">
          <label>(2.11)</label>
          <mml:math>
            <mml:mrow>
              <mml:mtext>Φ</mml:mtext>
              <mml:mrow>
                <mml:mo>(</mml:mo>
                <mml:mi>r</mml:mi>
                <mml:mo>)</mml:mo>
              </mml:mrow>
              <mml:mo>=</mml:mo>
              <mml:msup>
                <mml:mi>c</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mo>−</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:mi>G</mml:mi>
                  <mml:mi>m</mml:mi>
                </mml:mrow>
                <mml:mi>r</mml:mi>
              </mml:mfrac>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>In Equation (2.11), the parameter <inline-formula><mml:math><mml:mi> m </mml:mi></mml:math></inline-formula> is not assumed a priori to represent a material mass. It parametrizes the strength of the vacuum deficit itself. The proportionality constant relating deficit strength to far-field response will be identified in Section IV through comparison with the Newtonian limit. Equation (2.11) is introduced purely as a structural representation of the scalar vacuum-potential field; it is not yet a force law or dynamical equation.</p>
        <p>Scalar-potential formulations of gravitational phenomena, sometimes interpreted in terms of variations of <inline-formula><mml:math><mml:mrow><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:math></inline-formula> , appear in early relativistic developments by Einstein [<xref ref-type="bibr" rid="B11">11</xref>] and later in Machian or variable-speed-of-light approaches [<xref ref-type="bibr" rid="B12">12</xref>][<xref ref-type="bibr" rid="B19">19</xref>], although the physical interpretation adopted here is distinct.</p>
      </sec>
      <sec id="sec2dot5">
        <title>2.5. Universal Capacity Constraint on Vacuum Loading</title>
        <p>Because the vacuum potential is normalized relative to the finite reference value <inline-formula><mml:math><mml:mrow><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:math></inline-formula> , any localized mass configuration produces a deficit in the vacuum potential relative to this baseline. For a deficit parameter <inline-formula><mml:math><mml:mi> m </mml:mi></mml:math></inline-formula> distributed over a characteristic length scale <inline-formula><mml:math><mml:mi> L </mml:mi></mml:math></inline-formula> , the magnitude of the induced deficit is of order</p>
        <disp-formula id="FD13">
          <label>(2.12)</label>
          <mml:math>
            <mml:mrow>
              <mml:mtext>ΔΦ</mml:mtext>
              <mml:mo>∼</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:mi>G</mml:mi>
                  <mml:mi>m</mml:mi>
                </mml:mrow>
                <mml:mi>L</mml:mi>
              </mml:mfrac>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>Here <inline-formula><mml:math><mml:mrow><mml:mtext> ΔΦ </mml:mtext></mml:mrow></mml:math></inline-formula> represents the vacuum potential deficit relative to the reference level <inline-formula><mml:math><mml:mrow><mml:mtext> Φ </mml:mtext><mml:mo> = </mml:mo><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:math></inline-formula> . From Equations (2.10)-(2.11), the vacuum potential must remain bounded within the interval <inline-formula><mml:math><mml:mrow><mml:mn> 0 </mml:mn><mml:mo> ≤ </mml:mo><mml:mtext> Φ </mml:mtext><mml:mo> ≤ </mml:mo><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup><mml:mo> . </mml:mo></mml:mrow></mml:math></inline-formula></p>
        <disp-formula id="FD14">
          <label>(2.13)</label>
          <mml:math>
            <mml:mrow>
              <mml:mfrac>
                <mml:mrow>
                  <mml:mi>G</mml:mi>
                  <mml:mi>m</mml:mi>
                </mml:mrow>
                <mml:mi>L</mml:mi>
              </mml:mfrac>
              <mml:mo>≲</mml:mo>
              <mml:msup>
                <mml:mi>c</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>Equivalently,</p>
        <disp-formula id="FD15">
          <label>(2.14)</label>
          <mml:math>
            <mml:mrow>
              <mml:mfrac>
                <mml:mi>m</mml:mi>
                <mml:mi>L</mml:mi>
              </mml:mfrac>
              <mml:mo>≲</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:msup>
                    <mml:mi>c</mml:mi>
                    <mml:mn>2</mml:mn>
                  </mml:msup>
                </mml:mrow>
                <mml:mi>G</mml:mi>
              </mml:mfrac>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>This inequality expresses a universal capacity constraint on the vacuum potential deficit generated by localized mass configurations. A localized mass distribution imposes a vacuum loading, characterized by the mass-to-length ratio <inline-formula><mml:math><mml:mrow><mml:mrow><mml:mi> m </mml:mi><mml:mo> / </mml:mo><mml:mi> L </mml:mi></mml:mrow></mml:mrow></mml:math></inline-formula> , on the background vacuum capacity. The resulting deficit cannot exceed the finite reference capacity of the vacuum. This result follows directly from relativistic normalization and the finite reference value <inline-formula><mml:math><mml:mrow><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:math></inline-formula> , without invoking force laws, inertia, wave dynamics, or spacetime discreteness.</p>
      </sec>
      <sec id="sec2dot6">
        <title>2.6. Vacuum Field Response Postulate</title>
        <p>We finally postulate that the vacuum responds to spatial and temporal variations of <inline-formula><mml:math><mml:mtext> Φ </mml:mtext></mml:math></inline-formula> through local redistribution of vacuum potential. Differences <inline-formula><mml:math><mml:mrow><mml:mi> δ </mml:mi><mml:mtext> Φ </mml:mtext></mml:mrow></mml:math></inline-formula> drive this response, while the finite reference capacity <inline-formula><mml:math><mml:mrow><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:math></inline-formula> ensures bounded behavior.</p>
        <p>All gravitational, inertial, and wave phenomena developed in later sections arise from this response mechanism.</p>
      </sec>
    </sec>
    <sec id="sec3">
      <title>3. Section III—Mass, Vacuum-Potential Saturation, Localization, and Inertia</title>
      <p>In this section we analyze structural consequences of the vacuum-potential framework introduced in Section II. Finite vacuum capacity implies finite localization of vacuum loading, the existence of a collapse radius, the emergence of a distinguished minimal saturation threshold, and a structural interpretation of inertia.</p>
      <sec id="sec3dot1">
        <title>3.1. Mass as Integrated Vacuum Loading</title>
        <p>In Section II the vacuum was described by a scalar potential field <inline-formula><mml:math><mml:mrow><mml:mtext> Φ </mml:mtext><mml:mrow><mml:mo> ( </mml:mo><mml:mi> r </mml:mi><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> , normalized such that <inline-formula><mml:math display="inline"><mml:mrow><mml:mtext> Φ </mml:mtext><mml:mo> → </mml:mo><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup><mml:mtext> as </mml:mtext><mml:mi> r </mml:mi><mml:mo> → </mml:mo><mml:mi> ∞ </mml:mi></mml:mrow></mml:math></inline-formula> , corresponding to asymptotically flat spacetime. For a static, spherically symmetric configuration, the coarse-grained asymptotic solution takes the form</p>
        <disp-formula id="FD16">
          <label>(3.1)</label>
          <mml:math>
            <mml:mrow>
              <mml:mtext>Φ</mml:mtext>
              <mml:mrow>
                <mml:mo>(</mml:mo>
                <mml:mi>r</mml:mi>
                <mml:mo>)</mml:mo>
              </mml:mrow>
              <mml:mo>=</mml:mo>
              <mml:msup>
                <mml:mi>c</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mo>−</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:mi>G</mml:mi>
                  <mml:mi>m</mml:mi>
                </mml:mrow>
                <mml:mi>r</mml:mi>
              </mml:mfrac>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>The parameter <inline-formula><mml:math><mml:mi> m </mml:mi></mml:math></inline-formula> characterizes the total integrated vacuum deficit of the configuration. It is defined operationally through the Gauss-law relation</p>
        <disp-formula id="FD17">
          <label>(3.2)</label>
          <mml:math>
            <mml:mrow>
              <mml:mi>m</mml:mi>
              <mml:mo>=</mml:mo>
              <mml:mfrac>
                <mml:mn>1</mml:mn>
                <mml:mrow>
                  <mml:mn>4</mml:mn>
                  <mml:mi>π</mml:mi>
                  <mml:mi>G</mml:mi>
                </mml:mrow>
              </mml:mfrac>
              <mml:mstyle displaystyle="true">
                <mml:mrow>
                  <mml:msub>
                    <mml:mo>∮</mml:mo>
                    <mml:mrow>
                      <mml:msub>
                        <mml:mi>S</mml:mi>
                        <mml:mi>∞</mml:mi>
                      </mml:msub>
                    </mml:mrow>
                  </mml:msub>
                  <mml:mrow>
                    <mml:mo>∇</mml:mo>
                    <mml:mi>Φ</mml:mi>
                    <mml:mo>⋅</mml:mo>
                    <mml:mtext>d</mml:mtext>
                    <mml:mi>S</mml:mi>
                  </mml:mrow>
                </mml:mrow>
              </mml:mstyle>
              <mml:mo>,</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>where the surface integral is evaluated over a sphere at spatial infinity. Using Gauss’s theorem, this may equivalently be written as a volume integral,</p>
        <disp-formula id="FD18">
          <label>(3.3)</label>
          <mml:math>
            <mml:mrow>
              <mml:mi>m</mml:mi>
              <mml:mo>=</mml:mo>
              <mml:mfrac>
                <mml:mn>1</mml:mn>
                <mml:mrow>
                  <mml:mn>4</mml:mn>
                  <mml:mi>π</mml:mi>
                  <mml:mi>G</mml:mi>
                </mml:mrow>
              </mml:mfrac>
              <mml:mstyle displaystyle="true">
                <mml:mrow>
                  <mml:msub>
                    <mml:mo>∫</mml:mo>
                    <mml:mrow>
                      <mml:msup>
                        <mml:mi>ℝ</mml:mi>
                        <mml:mn>3</mml:mn>
                      </mml:msup>
                    </mml:mrow>
                  </mml:msub>
                  <mml:mrow>
                    <mml:msup>
                      <mml:mo>∇</mml:mo>
                      <mml:mn>2</mml:mn>
                    </mml:msup>
                    <mml:mtext>Φ</mml:mtext>
                    <mml:mrow>
                      <mml:mo>(</mml:mo>
                      <mml:mi>x</mml:mi>
                      <mml:mo>)</mml:mo>
                    </mml:mrow>
                    <mml:mtext>
                       
                    </mml:mtext>
                    <mml:msup>
                      <mml:mtext>d</mml:mtext>
                      <mml:mn>3</mml:mn>
                    </mml:msup>
                    <mml:mi>x</mml:mi>
                  </mml:mrow>
                </mml:mrow>
              </mml:mstyle>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>In Newtonian gravity, the gravitational potential <inline-formula><mml:math><mml:mrow><mml:msub><mml:mtext> Φ </mml:mtext><mml:mi> N </mml:mi></mml:msub></mml:mrow></mml:math></inline-formula> satisfies Poisson’s equation <inline-formula><mml:math><mml:mrow><mml:msup><mml:mo> ∇ </mml:mo><mml:mn> 2 </mml:mn></mml:msup><mml:msub><mml:mtext> Φ </mml:mtext><mml:mi> N </mml:mi></mml:msub><mml:mo> = </mml:mo><mml:mn> 4 </mml:mn><mml:mi> π </mml:mi><mml:mi> G </mml:mi><mml:mi> ρ </mml:mi><mml:mo> , </mml:mo></mml:mrow></mml:math></inline-formula> so outside a localized source (<inline-formula><mml:math><mml:mrow><mml:mi> ρ </mml:mi><mml:mo> = </mml:mo><mml:mn> 0 </mml:mn></mml:mrow></mml:math></inline-formula> ) one has <inline-formula><mml:math><mml:mrow><mml:msup><mml:mo> ∇ </mml:mo><mml:mn> 2 </mml:mn></mml:msup><mml:msub><mml:mtext> Φ </mml:mtext><mml:mi> N </mml:mi></mml:msub><mml:mo> = </mml:mo><mml:mn> 0. </mml:mn></mml:mrow></mml:math></inline-formula> In the exterior region, the potential satisfies Laplace’s equation, whose spherically symmetric solution yields the universal <inline-formula><mml:math><mml:mrow><mml:mrow><mml:mn> 1 </mml:mn><mml:mo> / </mml:mo><mml:mi> r </mml:mi></mml:mrow></mml:mrow></mml:math></inline-formula> behavior in Equation (3.1).</p>
        <p>Equations (3.2)-(3.3) show that <inline-formula><mml:math><mml:mi> m </mml:mi></mml:math></inline-formula> depends only on the global vacuum deficit and not on its detailed microscopic distribution. Different internal configurations that produce the same integrated loading yield identical asymptotic <inline-formula><mml:math><mml:mrow><mml:mrow><mml:mn> 1 </mml:mn><mml:mo> / </mml:mo><mml:mi> r </mml:mi></mml:mrow></mml:mrow></mml:math></inline-formula> behavior and therefore correspond to the same value of <inline-formula><mml:math><mml:mi> m </mml:mi></mml:math></inline-formula> .</p>
        <p>In this framework, mass is thus not postulated as an intrinsic point like substance but emerges as a global measure of vacuum deformation relative to the reference state <inline-formula><mml:math><mml:mrow><mml:mtext> Φ </mml:mtext><mml:mo> = </mml:mo><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:math></inline-formula> . This relational interpretation is consistent with Machian and emergent viewpoints in which inertial properties arise from vacuum structure rather than from fundamental particles [<xref ref-type="bibr" rid="B19">19</xref>]. Inertial and gravitational properties are encoded in this integrated vacuum loading.</p>
      </sec>
      <sec id="sec3dot2">
        <title>3.2. Capacity Constraint and Saturation</title>
        <p>Section II established the universal capacity bound</p>
        <disp-formula id="FD19">
          <label>(3.4)</label>
          <mml:math>
            <mml:mrow>
              <mml:mfrac>
                <mml:mi>m</mml:mi>
                <mml:mi>L</mml:mi>
              </mml:mfrac>
              <mml:mo>≲</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:msup>
                    <mml:mi>c</mml:mi>
                    <mml:mn>2</mml:mn>
                  </mml:msup>
                </mml:mrow>
                <mml:mi>G</mml:mi>
              </mml:mfrac>
              <mml:mo>,</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>for a configuration characterized by loading <inline-formula><mml:math><mml:mi> m </mml:mi></mml:math></inline-formula> distributed over a characteristic length scale <inline-formula><mml:math><mml:mi> L </mml:mi></mml:math></inline-formula> , defined as <inline-formula><mml:math><mml:mrow><mml:mo> = </mml:mo><mml:mfrac><mml:mi> m </mml:mi><mml:mi> L </mml:mi></mml:mfrac></mml:mrow></mml:math></inline-formula> . When the inequality is strictly satisfied, the vacuum response remains unsaturated. Saturation occurs when</p>
        <disp-formula id="FD20">
          <label>(3.5)</label>
          <mml:math>
            <mml:mrow>
              <mml:mfrac>
                <mml:mi>m</mml:mi>
                <mml:mi>L</mml:mi>
              </mml:mfrac>
              <mml:mo>=</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:msup>
                    <mml:mi>c</mml:mi>
                    <mml:mn>2</mml:mn>
                  </mml:msup>
                </mml:mrow>
                <mml:mi>G</mml:mi>
              </mml:mfrac>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>We refer to this threshold a<bold>s</bold>vacuum-potential saturation<bold>, co</bold>rresponding to the onset of vacuum-capacity collapse.</p>
        <p>Collapse in this framework does not correspond to geometric compression or curvature divergence. It signifies that the local deficit relative to the reference capacity <inline-formula><mml:math><mml:mrow><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:math></inline-formula> has reached its maximal permitted magnitude. Beyond this point, further localization at fixed <inline-formula><mml:math><mml:mi> L </mml:mi></mml:math></inline-formula> cannot increase the deficit.</p>
      </sec>
      <sec id="sec3dot3">
        <title>3.3. Finite Localization and Collapse Radius</title>
        <p>Because the vacuum-potential field has finite capacity, a given loading <inline-formula><mml:math><mml:mi> m </mml:mi></mml:math></inline-formula> cannot be confined to arbitrarily small regions.</p>
        <p>Define the collapse radius <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> r </mml:mi><mml:mi> c </mml:mi></mml:msub></mml:mrow></mml:math></inline-formula> as the scale at which the deficit relative to the reference value reaches order <inline-formula><mml:math><mml:mrow><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:math></inline-formula> ,</p>
        <disp-formula id="FD21">
          <label>(3.6)</label>
          <mml:math>
            <mml:mrow>
              <mml:msup>
                <mml:mi>c</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mo>−</mml:mo>
              <mml:mtext>Φ</mml:mtext>
              <mml:mrow>
                <mml:mo>(</mml:mo>
                <mml:mrow>
                  <mml:msub>
                    <mml:mi>r</mml:mi>
                    <mml:mi>c</mml:mi>
                  </mml:msub>
                </mml:mrow>
                <mml:mo>)</mml:mo>
              </mml:mrow>
              <mml:mo>∼</mml:mo>
              <mml:msup>
                <mml:mi>c</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>Using the continuum profile (3.1),</p>
        <disp-formula id="FD22">
          <mml:math>
            <mml:mrow>
              <mml:msup>
                <mml:mi>c</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mo>−</mml:mo>
              <mml:mtext>Φ</mml:mtext>
              <mml:mrow>
                <mml:mo>(</mml:mo>
                <mml:mi>r</mml:mi>
                <mml:mo>)</mml:mo>
              </mml:mrow>
              <mml:mo>=</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:mi>G</mml:mi>
                  <mml:mi>m</mml:mi>
                </mml:mrow>
                <mml:mi>r</mml:mi>
              </mml:mfrac>
              <mml:mo>,</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>we obtain</p>
        <disp-formula id="FD23">
          <label>(3.7)</label>
          <mml:math>
            <mml:mrow>
              <mml:msub>
                <mml:mi>r</mml:mi>
                <mml:mi>c</mml:mi>
              </mml:msub>
              <mml:mo>∼</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:mi>G</mml:mi>
                  <mml:mi>m</mml:mi>
                </mml:mrow>
                <mml:mrow>
                  <mml:msup>
                    <mml:mi>c</mml:mi>
                    <mml:mn>2</mml:mn>
                  </mml:msup>
                </mml:mrow>
              </mml:mfrac>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>Thus any finite vacuum loading localizes over a finite region. Arbitrary compression to vanishing spatial extent is excluded solely by finite vacuum capacity, independent of additional field equations or geometric assumptions.</p>
      </sec>
      <sec id="sec3dot4">
        <title>3.4. Distinguished Minimal Response Scale</title>
        <p>If the vacuum admits a minimal response scale <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> ℓ </mml:mi><mml:mo> * </mml:mo></mml:msub></mml:mrow></mml:math></inline-formula> , below which the continuum description ceases to apply, a distinguished limiting case arises when</p>
        <disp-formula id="FD24">
          <label>(3.8)</label>
          <mml:math>
            <mml:mrow>
              <mml:msub>
                <mml:mi>r</mml:mi>
                <mml:mi>c</mml:mi>
              </mml:msub>
              <mml:mo>∼</mml:mo>
              <mml:msub>
                <mml:mi>ℓ</mml:mi>
                <mml:mo>*</mml:mo>
              </mml:msub>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>Substituting Equation (3.8) into Equation (3.7) yields</p>
        <disp-formula id="FD25">
          <label>(3.9)</label>
          <mml:math>
            <mml:mrow>
              <mml:mi>m</mml:mi>
              <mml:mo>∼</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:msup>
                    <mml:mi>c</mml:mi>
                    <mml:mn>2</mml:mn>
                  </mml:msup>
                  <mml:msub>
                    <mml:mi>ℓ</mml:mi>
                    <mml:mo>*</mml:mo>
                  </mml:msub>
                </mml:mrow>
                <mml:mi>G</mml:mi>
              </mml:mfrac>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>This defines a threshold mass corresponding to saturation at the minimal response scale. When <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> ℓ </mml:mi><mml:mo> * </mml:mo></mml:msub></mml:mrow></mml:math></inline-formula> is later identified via quantum action considerations with the Planck length (<inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> ℓ </mml:mi><mml:mi> P </mml:mi></mml:msub><mml:mo stretchy="false"> ) </mml:mo></mml:mrow></mml:math></inline-formula> , Equation (3.9) reproduces the Planck mass <inline-formula><mml:math><mml:mrow><mml:mrow><mml:mo> ( </mml:mo><mml:mrow><mml:msub><mml:mi> m </mml:mi><mml:mi> P </mml:mi></mml:msub></mml:mrow><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> . Importantly, this threshold is not postulated here. It emerges as a limiting case of capacity saturation once a minimal response scale is independently introduced. For loadings <inline-formula><mml:math><mml:mi> m </mml:mi></mml:math></inline-formula> exceeding this threshold, saturation is already achieved at <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> ℓ </mml:mi><mml:mo> * </mml:mo></mml:msub></mml:mrow></mml:math></inline-formula> , and further localization is not possible.</p>
      </sec>
      <sec id="sec3dot5">
        <title>3.5. Boundedness and Absence of Singular Behaviour</title>
        <p>Because vacuum loading is capacity-limited, the scalar vacuum-potential field remains bounded for all physically realized configurations.</p>
        <p>The continuum expression (3.1) does not extend to arbitrarily small <inline-formula><mml:math><mml:mi> r </mml:mi></mml:math></inline-formula> ; it ceases to apply once saturation is reached. Therefore no divergence of the vacuum-potential field is physically realized.</p>
        <p>In this sense, pointlike singular behavior is replaced by finite saturation regions whose size is determined by total loading and vacuum bounded capacity. Similar regularization mechanisms appear in nonsingular black-hole models and quantum-gravity approaches derived from different principles [<xref ref-type="bibr" rid="B20">20</xref>]-[<xref ref-type="bibr" rid="B22">22</xref>]. In the present framework, boundedness follows directly from finite vacuum capacity.</p>
      </sec>
      <sec id="sec3dot6">
        <title>3.6. Structural Origin of Inertia</title>
        <p>Consider a configuration characterized by total loading <inline-formula><mml:math><mml:mi> m </mml:mi></mml:math></inline-formula> . Any displacement, deformation, or acceleration requires redistribution of the associated vacuum-potential deficit across the network. Because redistribution is local and capacity-limited, such reconfiguration incurs energetic cost. The larger the loading <inline-formula><mml:math><mml:mi> m </mml:mi></mml:math></inline-formula> , the greater the resistance to rapid redistribution.</p>
        <p>Inertia therefore emerges as resistance of the vacuum to changes in the configuration of a given loading. At this stage this statement is structural rather than dynamical; no force law or equation of motion is assumed.</p>
        <p>This interpretation is consistent with relational accounts of inertia proposed in earlier work [<xref ref-type="bibr" rid="B19">19</xref>][<xref ref-type="bibr" rid="B23">23</xref>].</p>
      </sec>
    </sec>
    <sec id="sec4">
      <title>4. Section IV—Static Response and Emergent Gravitational Interaction</title>
      <p>We now analyze the static response regime of the vacuum-potential field, in one dimensional response for spherically symmetric configuration, the potential depends only on the radial coordinate <inline-formula><mml:math display="inline"><mml:mrow><mml:mi> r </mml:mi><mml:mo> = </mml:mo><mml:mrow><mml:mo> | </mml:mo><mml:mi> x </mml:mi><mml:mo> | </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> , <inline-formula><mml:math display="inline"><mml:mrow><mml:mi> Φ </mml:mi><mml:mrow><mml:mo> ( </mml:mo><mml:mi> x </mml:mi><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> introduced in Sections II and III. In the bounded-vacuum framework, gravitation does not arise from a fundamental interaction law but from static relaxation of a bounded vacuum-potential deficit. The same scalar field that characterizes vacuum loading produces gravitational attraction when the configuration is time-independent, consistent with relational and vacuum-based perspectives on gravity and inertia [<xref ref-type="bibr" rid="B7">7</xref>][<xref ref-type="bibr" rid="B19">19</xref>].</p>
      <p>A localized vacuum loading <inline-formula><mml:math><mml:mi> m </mml:mi></mml:math></inline-formula> corresponds to a persistent deficit relative to the reference state <inline-formula><mml:math><mml:mrow><mml:mtext> Φ </mml:mtext><mml:mo> = </mml:mo><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:math></inline-formula> . In the static regime, the vacuum field relaxes toward its maximal-capacity configuration far from any excitation,</p>
      <disp-formula id="FD26">
        <label>(4.1)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>Φ</mml:mi>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>x</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>→</mml:mo>
            <mml:msup>
              <mml:mi>c</mml:mi>
              <mml:mn>2</mml:mn>
            </mml:msup>
            <mml:mo>
            </mml:mo>
            <mml:mtext>as</mml:mtext>
            <mml:mrow>
              <mml:mo>|</mml:mo>
              <mml:mi>x</mml:mi>
              <mml:mo>|</mml:mo>
            </mml:mrow>
            <mml:mo>→</mml:mo>
            <mml:mi>∞</mml:mi>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>A test configuration characterized by loading <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> m </mml:mi><mml:mi> t </mml:mi></mml:msub></mml:mrow></mml:math></inline-formula> placed in this static background possesses a position-dependent vacuum-field energy</p>
      <disp-formula id="FD27">
        <label>(4.2)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>E</mml:mi>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>x</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>=</mml:mo>
            <mml:msub>
              <mml:mi>m</mml:mi>
              <mml:mi>t</mml:mi>
            </mml:msub>
            <mml:mtext>
               
            </mml:mtext>
            <mml:mtext>Φ</mml:mtext>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>x</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>,</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>which follows directly from the interpretation of mass as integrated vacuum loading established in Section III. No additional coupling principle or interaction term is introduced; the energy arises from embedding the test loading within the vacuum-potential field.</p>
      <p>In static systems, force is defined operationally as the spatial gradient of stored energy [<xref ref-type="bibr" rid="B24">24</xref>]. Accordingly,</p>
      <disp-formula id="FD28">
        <label>(4.3)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>F</mml:mi>
            <mml:mo>≡</mml:mo>
            <mml:mo>−</mml:mo>
            <mml:mo>∇</mml:mo>
            <mml:mi>E</mml:mi>
            <mml:mo>=</mml:mo>
            <mml:mo>−</mml:mo>
            <mml:msub>
              <mml:mi>m</mml:mi>
              <mml:mi>t</mml:mi>
            </mml:msub>
            <mml:mo>∇</mml:mo>
            <mml:mtext>Φ</mml:mtext>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>Force is therefore not fundamental in the framework; it emerges from spatial variation of the vacuum potential. Dividing by <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> m </mml:mi><mml:mi> t </mml:mi></mml:msub></mml:mrow></mml:math></inline-formula> gives the acceleration,</p>
      <disp-formula id="FD29">
        <label>(4.4)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>a</mml:mi>
            <mml:mo>=</mml:mo>
            <mml:mo>−</mml:mo>
            <mml:mo>∇</mml:mo>
            <mml:mtext>Φ</mml:mtext>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>Acceleration is thus determined entirely by gradients of the vacuum field, and it is independent of the magnitude of the test loading <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> m </mml:mi><mml:mi> t </mml:mi></mml:msub></mml:mrow></mml:math></inline-formula> . The equality of inertial and gravitational mass therefore follows directly from the structure of the vacuum-potential energy <inline-formula><mml:math><mml:mrow><mml:mi> E </mml:mi><mml:mo> = </mml:mo><mml:msub><mml:mi> m </mml:mi><mml:mi> t </mml:mi></mml:msub><mml:mtext> Φ </mml:mtext></mml:mrow></mml:math></inline-formula> and does not require an independent equivalence postulate. Universality of free fall emerges as a consequence of vacuum response, rather than as a fundamental principle imposed a priori.</p>
      <p>We now determine the static profile <inline-formula><mml:math><mml:mrow><mml:mtext> Φ </mml:mtext><mml:mrow><mml:mo> ( </mml:mo><mml:mi> r </mml:mi><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> associated with a spherically symmetric vacuum loading <inline-formula><mml:math><mml:mi> m </mml:mi></mml:math></inline-formula> . The solution must satisfy asymptotic relaxation <inline-formula><mml:math><mml:mrow><mml:mtext> Φ </mml:mtext><mml:mo> → </mml:mo><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:math></inline-formula> as <inline-formula><mml:math><mml:mrow><mml:mi> r </mml:mi><mml:mo> → </mml:mo><mml:mi> ∞ </mml:mi></mml:mrow></mml:math></inline-formula> , isotropy, and the finite localization scale <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> r </mml:mi><mml:mi> c </mml:mi></mml:msub><mml:mo> ∼ </mml:mo><mml:mrow><mml:mrow><mml:mi> G </mml:mi><mml:mi> m </mml:mi></mml:mrow><mml:mo> / </mml:mo><mml:mrow><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:mrow></mml:mrow></mml:math></inline-formula> derived in Section III. At distances large compared with <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> r </mml:mi><mml:mi> c </mml:mi></mml:msub></mml:mrow></mml:math></inline-formula> , the leading-order coarse-grained relaxation profile consistent with these requirements takes the form</p>
      <disp-formula id="FD30">
        <label>(4.5)</label>
        <mml:math>
          <mml:mrow>
            <mml:mtext>Φ</mml:mtext>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>r</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>=</mml:mo>
            <mml:msup>
              <mml:mi>c</mml:mi>
              <mml:mn>2</mml:mn>
            </mml:msup>
            <mml:mo>−</mml:mo>
            <mml:mfrac>
              <mml:mrow>
                <mml:mi>G</mml:mi>
                <mml:mi>m</mml:mi>
              </mml:mrow>
              <mml:mi>r</mml:mi>
            </mml:mfrac>
            <mml:mo>,</mml:mo>
            <mml:mi>r</mml:mi>
            <mml:mo>≫</mml:mo>
            <mml:msub>
              <mml:mi>r</mml:mi>
              <mml:mi>c</mml:mi>
            </mml:msub>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>The constant <italic>G</italic> appearing in Equation (4.5) is not introduced as a fundamental gravitational parameter but is fixed by matching the far-field relaxation profile to the observed Newtonian limit. It therefore acquires the interpretation of a transmissibility coefficient of vacuum-potential deficits, quantifying the response strength of the vacuum medium. Equation (4.5) is not postulated as a gravitational law but represents the asymptotic static relaxation profile of a bounded scalar field sourced by a localized vacuum loading. Analogous long-range equilibrium profiles arise in condensed-matter and analogue-gravity systems in which macroscopic fields emerge from relaxation of an underlying medium [<xref ref-type="bibr" rid="B7">7</xref>][<xref ref-type="bibr" rid="B10">10</xref>].</p>
      <p>Substituting Equation (4.5) into Equation (4.3) yields</p>
      <disp-formula id="FD31">
        <label>(4.6)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>F</mml:mi>
            <mml:mo>=</mml:mo>
            <mml:mo>−</mml:mo>
            <mml:msub>
              <mml:mi>m</mml:mi>
              <mml:mi>t</mml:mi>
            </mml:msub>
            <mml:mo>∇</mml:mo>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mrow>
                <mml:msup>
                  <mml:mi>c</mml:mi>
                  <mml:mn>2</mml:mn>
                </mml:msup>
                <mml:mo>−</mml:mo>
                <mml:mfrac>
                  <mml:mrow>
                    <mml:mi>G</mml:mi>
                    <mml:mi>m</mml:mi>
                  </mml:mrow>
                  <mml:mi>r</mml:mi>
                </mml:mfrac>
              </mml:mrow>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>=</mml:mo>
            <mml:mo>−</mml:mo>
            <mml:mfrac>
              <mml:mrow>
                <mml:mi>G</mml:mi>
                <mml:mi>m</mml:mi>
                <mml:msub>
                  <mml:mi>m</mml:mi>
                  <mml:mi>t</mml:mi>
                </mml:msub>
              </mml:mrow>
              <mml:mrow>
                <mml:msup>
                  <mml:mi>r</mml:mi>
                  <mml:mn>2</mml:mn>
                </mml:msup>
              </mml:mrow>
            </mml:mfrac>
            <mml:mtext>
               
            </mml:mtext>
            <mml:mover accent="true">
              <mml:mi>r</mml:mi>
              <mml:mo>^</mml:mo>
            </mml:mover>
            <mml:mo>,</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>recovering Newton’s inverse-square law [<xref ref-type="bibr" rid="B10">10</xref>] as an emergent static response of the vacuum field. Gravitation in the bounded-vacuum framework is therefore interpreted as the tendency of the vacuum to reduce spatial gradients in the bounded scalar potential <inline-formula><mml:math><mml:mtext> Φ </mml:mtext></mml:math></inline-formula> , consistent with vacuum-based and emergent-gravity viewpoints [<xref ref-type="bibr" rid="B7">7</xref>][<xref ref-type="bibr" rid="B10">10</xref>][<xref ref-type="bibr" rid="B23">23</xref>].</p>
      <p>The static gravitational response developed here and the time-dependent vacuum redistribution analyzed in subsequent sections arise from the same scalar field <inline-formula><mml:math><mml:mtext> Φ </mml:mtext></mml:math></inline-formula> . The distinction between gravitation and wave propagation is not one of field type but of response regime: time-independent relaxation versus time-dependent redistribution. Because both regimes are governed by the same finite vacuum capacity introduced in Section II, accelerations, forces, tensions, and signal speeds are constrained by the transmissibility of the vacuum field itself [<xref ref-type="bibr" rid="B7">7</xref>][<xref ref-type="bibr" rid="B10">10</xref>]. This unified field-response perspective prepares the ground for Section V, where we show that bounded vacuum capacity implies a universal maximum transmissible tension and a universal signal-speed bound identified with <inline-formula><mml:math><mml:mi> c </mml:mi></mml:math></inline-formula> .</p>
    </sec>
    <sec id="sec5">
      <title>5. Section V—Emergent Force, Tension, and Signal-Speed Bounds</title>
      <p>In this section we show that finite vacuum-potential capacity in the vacuum-space implies universal upper bounds on force, transmissible tension, and signal propagation speed. These bounds arise directly from vacuum loading constraints established in Sections II-IV. No spacetime geometry, Lorentz symmetry, or independent kinematic postulate is assumed.</p>
      <sec id="sec5dot1">
        <title>5.1. Vacuum Loading, Force, and Maximum Tension</title>
        <p>From Section IV, a localized vacuum-potential deficit relative to the reference value <inline-formula><mml:math><mml:mrow><mml:mtext> Φ </mml:mtext><mml:mo> = </mml:mo><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:math></inline-formula> carries energy</p>
        <disp-formula id="FD32">
          <label>(5.1)</label>
          <mml:math>
            <mml:mrow>
              <mml:mtext>Δ</mml:mtext>
              <mml:mi>E</mml:mi>
              <mml:mo>=</mml:mo>
              <mml:mi>m</mml:mi>
              <mml:mtext>
                 
              </mml:mtext>
              <mml:mtext>ΔΦ</mml:mtext>
              <mml:mo>,</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>where <inline-formula><mml:math><mml:mi> m </mml:mi></mml:math></inline-formula> denotes the total vacuum loading and <inline-formula><mml:math><mml:mrow><mml:mtext> ΔΦ </mml:mtext></mml:mrow></mml:math></inline-formula> the local deficit magnitude.</p>
        <p>If this energy is redistributed across a characteristic separation <inline-formula><mml:math><mml:mi> L </mml:mi></mml:math></inline-formula> , the associated force scale is</p>
        <disp-formula id="FD33">
          <label>(5.2)</label>
          <mml:math>
            <mml:mrow>
              <mml:mi>F</mml:mi>
              <mml:mo>∼</mml:mo>
              <mml:mrow>
                <mml:mo>|</mml:mo>
                <mml:mrow>
                  <mml:mfrac>
                    <mml:mrow>
                      <mml:mtext>d</mml:mtext>
                      <mml:mi>E</mml:mi>
                    </mml:mrow>
                    <mml:mrow>
                      <mml:mtext>d</mml:mtext>
                      <mml:mi>r</mml:mi>
                    </mml:mrow>
                  </mml:mfrac>
                </mml:mrow>
                <mml:mo>|</mml:mo>
              </mml:mrow>
              <mml:mo>∼</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:mtext>Δ</mml:mtext>
                  <mml:mi>E</mml:mi>
                </mml:mrow>
                <mml:mi>L</mml:mi>
              </mml:mfrac>
              <mml:mo>,</mml:mo>
              <mml:mtext>Δ</mml:mtext>
              <mml:mi>E</mml:mi>
              <mml:mo>≡</mml:mo>
              <mml:mi>m</mml:mi>
              <mml:mtext>
                 
              </mml:mtext>
              <mml:mtext>ΔΦ</mml:mtext>
              <mml:mo>⇒</mml:mo>
              <mml:mtext>
              </mml:mtext>
              <mml:mi>F</mml:mi>
              <mml:mo>∼</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:mi>m</mml:mi>
                  <mml:mtext>
                     
                  </mml:mtext>
                  <mml:mtext>ΔΦ</mml:mtext>
                </mml:mrow>
                <mml:mi>L</mml:mi>
              </mml:mfrac>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>Both factors in Equation (5.2) are independently bounded.</p>
        <p>First, the vacuum-potential deficit cannot exceed the reference magnitude,</p>
        <disp-formula id="FD34">
          <label>(5.3)</label>
          <mml:math>
            <mml:mrow>
              <mml:mtext>ΔΦ</mml:mtext>
              <mml:mo>≤</mml:mo>
              <mml:msup>
                <mml:mi>c</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mo>,</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>as established in Section II.</p>
        <p>Second, the vacuum loading <inline-formula><mml:math><mml:mrow><mml:mrow><mml:mo> ( </mml:mo><mml:mrow><mml:mi> μ </mml:mi><mml:mo> = </mml:mo><mml:mfrac><mml:mi> m </mml:mi><mml:mi> L </mml:mi></mml:mfrac></mml:mrow><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> obeys the saturation bound derived in Section III,</p>
        <disp-formula id="FD35">
          <label>(5.4)</label>
          <mml:math>
            <mml:mrow>
              <mml:mi>μ</mml:mi>
              <mml:mo>=</mml:mo>
              <mml:mfrac>
                <mml:mi>m</mml:mi>
                <mml:mi>L</mml:mi>
              </mml:mfrac>
              <mml:mo>≤</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:msup>
                    <mml:mi>c</mml:mi>
                    <mml:mn>2</mml:mn>
                  </mml:msup>
                </mml:mrow>
                <mml:mi>G</mml:mi>
              </mml:mfrac>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>Combining Equations (5.2)-(5.4) yields a universal upper bound on force,</p>
        <disp-formula id="FD36">
          <label>(5.5)</label>
          <mml:math>
            <mml:mrow>
              <mml:mi>F</mml:mi>
              <mml:mo>≤</mml:mo>
              <mml:msub>
                <mml:mi>F</mml:mi>
                <mml:mrow>
                  <mml:mtext>max</mml:mtext>
                </mml:mrow>
              </mml:msub>
              <mml:mo>≡</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:msup>
                    <mml:mi>c</mml:mi>
                    <mml:mn>4</mml:mn>
                  </mml:msup>
                </mml:mrow>
                <mml:mi>G</mml:mi>
              </mml:mfrac>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>This value coincides numerically with the maximum-force or maximum-tension scale discussed in gravitational contexts using horizon and thermodynamic arguments [<xref ref-type="bibr" rid="B4">4</xref>]-[<xref ref-type="bibr" rid="B6">6</xref>]. In the bounded-vacuum framework, however, it arises directly from finite vacuum capacity and bounded loading.</p>
        <p>Because force transmission corresponds to tension along the vacuum network, Equation (5.5) defines a maximum transmissible tension,</p>
        <disp-formula id="FD37">
          <label>(5.6)</label>
          <mml:math>
            <mml:mrow>
              <mml:msub>
                <mml:mi>T</mml:mi>
                <mml:mrow>
                  <mml:mtext>max</mml:mtext>
                </mml:mrow>
              </mml:msub>
              <mml:mo>=</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:msup>
                    <mml:mi>c</mml:mi>
                    <mml:mn>4</mml:mn>
                  </mml:msup>
                </mml:mrow>
                <mml:mi>G</mml:mi>
              </mml:mfrac>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>No larger force or tension can be supported without violating either vacuum capacity or the collapse condition derived in Section III.</p>
        <p>It is worth noting that in general-relativistic discussions the maximum-force (or maximum-tension) scale is sometimes quoted with an additional numerical factor, e.g. <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> F </mml:mi><mml:mrow><mml:mtext> max </mml:mtext></mml:mrow></mml:msub><mml:mo> = </mml:mo><mml:mrow><mml:mrow><mml:msup><mml:mi> c </mml:mi><mml:mn> 4 </mml:mn></mml:msup></mml:mrow><mml:mo> / </mml:mo><mml:mrow><mml:mrow><mml:mo> ( </mml:mo><mml:mrow><mml:mn> 4 </mml:mn><mml:mi> G </mml:mi></mml:mrow><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:mrow></mml:mrow></mml:math></inline-formula> , depending on the geometric normalization adopted in horizon or surface-gravity arguments [<xref ref-type="bibr" rid="B4">4</xref>]-[<xref ref-type="bibr" rid="B6">6</xref>]. Such order-unity factors arise from specific metric conventions (e.g., the factor of 2 in the Schwarzschild radius and the associated surface gravity). In contrast, within the bounded-vacuum framework the bound <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> T </mml:mi><mml:mrow><mml:mtext> max </mml:mtext></mml:mrow></mml:msub><mml:mo> = </mml:mo><mml:mrow><mml:mrow><mml:msup><mml:mi> c </mml:mi><mml:mn> 4 </mml:mn></mml:msup></mml:mrow><mml:mo> / </mml:mo><mml:mi> G </mml:mi></mml:mrow></mml:mrow></mml:math></inline-formula> follows directly from the loading constraint <inline-formula><mml:math><mml:mrow><mml:mrow><mml:mi> m </mml:mi><mml:mo> / </mml:mo><mml:mi> L </mml:mi></mml:mrow><mml:mo> ≤ </mml:mo><mml:mrow><mml:mrow><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow><mml:mo> / </mml:mo><mml:mi> G </mml:mi></mml:mrow></mml:mrow></mml:math></inline-formula> , independent of any particular horizon geometry. The precise numerical correspondence with GR therefore depends on whether spatial-curvature contributions are incorporated in the effective description.</p>
      </sec>
      <sec id="sec5dot2">
        <title>5.2. Emergent Universal Signal-Speed Bound</title>
        <p>In the bounded-vacuum framework the physical state of the vacuum is characterized by the scalar capacity field <inline-formula><mml:math><mml:mrow><mml:mtext> Φ </mml:mtext><mml:mrow><mml:mo> ( </mml:mo><mml:mrow><mml:mi> x </mml:mi><mml:mo> , </mml:mo><mml:mi> t </mml:mi></mml:mrow><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> . The homogeneous equilibrium vacuum corresponds to the maximal capacity state <inline-formula><mml:math><mml:mrow><mml:msub><mml:mtext> Φ </mml:mtext><mml:mn> 0 </mml:mn></mml:msub><mml:mo> = </mml:mo><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup><mml:mo> . </mml:mo></mml:mrow></mml:math></inline-formula> Dynamical signals correspond to small redistributions of this capacity about the equilibrium value. It is therefore convenient to introduce the deviation field</p>
        <disp-formula id="FD38">
          <label>(5.7)</label>
          <mml:math>
            <mml:mrow>
              <mml:mi>ϕ</mml:mi>
              <mml:mrow>
                <mml:mo>(</mml:mo>
                <mml:mrow>
                  <mml:mi>x</mml:mi>
                  <mml:mo>,</mml:mo>
                  <mml:mi>t</mml:mi>
                </mml:mrow>
                <mml:mo>)</mml:mo>
              </mml:mrow>
              <mml:mo>≡</mml:mo>
              <mml:mtext>Φ</mml:mtext>
              <mml:mrow>
                <mml:mo>(</mml:mo>
                <mml:mrow>
                  <mml:mi>x</mml:mi>
                  <mml:mo>,</mml:mo>
                  <mml:mi>t</mml:mi>
                </mml:mrow>
                <mml:mo>)</mml:mo>
              </mml:mrow>
              <mml:mo>−</mml:mo>
              <mml:msup>
                <mml:mi>c</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>With this definition the relaxed vacuum satisfies <inline-formula><mml:math><mml:mrow><mml:mi> ϕ </mml:mi><mml:mo> = </mml:mo><mml:mn> 0 </mml:mn></mml:mrow></mml:math></inline-formula> , while localized matter configurations correspond to negative deviations <inline-formula><mml:math><mml:mrow><mml:mi> ϕ </mml:mi><mml:mo> &lt; </mml:mo><mml:mn> 0 </mml:mn></mml:mrow></mml:math></inline-formula> , reflecting the deficit of vacuum capacity relative to the asymptotic state. For the static configuration discussed in Section III the deviation reduces to <inline-formula><mml:math><mml:mrow><mml:mi> ϕ </mml:mi><mml:mrow><mml:mo> ( </mml:mo><mml:mi> r </mml:mi><mml:mo> ) </mml:mo></mml:mrow><mml:mo> = </mml:mo><mml:mo> − </mml:mo><mml:mfrac><mml:mrow><mml:mi> G </mml:mi><mml:mi> m </mml:mi></mml:mrow><mml:mi> r </mml:mi></mml:mfrac></mml:mrow></mml:math></inline-formula> , which represents the local reduction of vacuum capacity produced by a localized loading <inline-formula><mml:math><mml:mi> m </mml:mi></mml:math></inline-formula> . In the present section we consider general dynamical perturbations <inline-formula><mml:math><mml:mrow><mml:mi> ϕ </mml:mi><mml:mrow><mml:mo> ( </mml:mo><mml:mrow><mml:mi> x </mml:mi><mml:mo> , </mml:mo><mml:mi> t </mml:mi></mml:mrow><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> .</p>
        <p>At length scales large compared with the microscopic structure of the vacuum network, the dynamics of small perturbations is governed by the lowest-order local action consistent with translational symmetry and quadratic order in derivatives,</p>
        <disp-formula id="FD39">
          <label>(5.8)</label>
          <mml:math>
            <mml:mrow>
              <mml:mi>S</mml:mi>
              <mml:mo>=</mml:mo>
              <mml:mstyle displaystyle="true">
                <mml:mrow>
                  <mml:mo>∫</mml:mo>
                  <mml:mrow>
                    <mml:mtext>d</mml:mtext>
                    <mml:mi>t</mml:mi>
                    <mml:msup>
                      <mml:mtext>d</mml:mtext>
                      <mml:mn>3</mml:mn>
                    </mml:msup>
                    <mml:mi>x</mml:mi>
                  </mml:mrow>
                </mml:mrow>
              </mml:mstyle>
              <mml:mrow>
                <mml:mo>[</mml:mo>
                <mml:mrow>
                  <mml:mfrac>
                    <mml:mn>1</mml:mn>
                    <mml:mn>2</mml:mn>
                  </mml:mfrac>
                  <mml:mi>μ</mml:mi>
                  <mml:msup>
                    <mml:mrow>
                      <mml:mrow>
                        <mml:mo>(</mml:mo>
                        <mml:mrow>
                          <mml:msub>
                            <mml:mo>∂</mml:mo>
                            <mml:mi>t</mml:mi>
                          </mml:msub>
                          <mml:mi>ϕ</mml:mi>
                        </mml:mrow>
                        <mml:mo>)</mml:mo>
                      </mml:mrow>
                    </mml:mrow>
                    <mml:mn>2</mml:mn>
                  </mml:msup>
                  <mml:mo>−</mml:mo>
                  <mml:mfrac>
                    <mml:mn>1</mml:mn>
                    <mml:mn>2</mml:mn>
                  </mml:mfrac>
                  <mml:mi>T</mml:mi>
                  <mml:msup>
                    <mml:mrow>
                      <mml:mrow>
                        <mml:mo>(</mml:mo>
                        <mml:mrow>
                          <mml:mo>∇</mml:mo>
                          <mml:mi>ϕ</mml:mi>
                        </mml:mrow>
                        <mml:mo>)</mml:mo>
                      </mml:mrow>
                    </mml:mrow>
                    <mml:mn>2</mml:mn>
                  </mml:msup>
                </mml:mrow>
                <mml:mo>]</mml:mo>
              </mml:mrow>
              <mml:mo>,</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>where <inline-formula><mml:math><mml:mi> μ </mml:mi></mml:math></inline-formula> represents the effective inertial loading density of the vacuum and <inline-formula><mml:math><mml:mrow><mml:mi> T </mml:mi><mml:mo></mml:mo></mml:mrow></mml:math></inline-formula> is the transmissible vacuum tension. Variation of the action yields the Euler-Lagrange equation</p>
        <disp-formula id="FD40">
          <label>(5.9)</label>
          <mml:math>
            <mml:mrow>
              <mml:mi>μ</mml:mi>
              <mml:mtext>
                 
              </mml:mtext>
              <mml:msubsup>
                <mml:mo>∂</mml:mo>
                <mml:mi>t</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msubsup>
              <mml:mi>ϕ</mml:mi>
              <mml:mo>=</mml:mo>
              <mml:mi>T</mml:mi>
              <mml:mtext>
                 
              </mml:mtext>
              <mml:msup>
                <mml:mo>∇</mml:mo>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mi>ϕ</mml:mi>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>For plane-wave solutions <inline-formula><mml:math><mml:mrow><mml:mi> ϕ </mml:mi><mml:mo> ∝ </mml:mo><mml:msup><mml:mtext> e </mml:mtext><mml:mrow><mml:mi> i </mml:mi><mml:mrow><mml:mo> ( </mml:mo><mml:mrow><mml:mi> k </mml:mi><mml:mo> ⋅ </mml:mo><mml:mi> x </mml:mi><mml:mo> − </mml:mo><mml:mi> ω </mml:mi><mml:mi> t </mml:mi></mml:mrow><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:msup></mml:mrow></mml:math></inline-formula> ,</p>
        <disp-formula id="FD41">
          <label>(5.10)</label>
          <mml:math>
            <mml:mrow>
              <mml:msup>
                <mml:mi>ω</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mo>=</mml:mo>
              <mml:mfrac>
                <mml:mi>T</mml:mi>
                <mml:mi>μ</mml:mi>
              </mml:mfrac>
              <mml:msup>
                <mml:mi>k</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mo>,</mml:mo>
              <mml:mi>v</mml:mi>
              <mml:mo>≡</mml:mo>
              <mml:mfrac>
                <mml:mi>ω</mml:mi>
                <mml:mi>k</mml:mi>
              </mml:mfrac>
              <mml:mo>=</mml:mo>
              <mml:msqrt>
                <mml:mrow>
                  <mml:mfrac>
                    <mml:mi>T</mml:mi>
                    <mml:mi>μ</mml:mi>
                  </mml:mfrac>
                </mml:mrow>
              </mml:msqrt>
              <mml:mo>,</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>so that the characteristic propagation speed is determined by the stiffness-to-inertia ratio of the vacuum response.</p>
        <p>Both <inline-formula><mml:math><mml:mi> T </mml:mi></mml:math></inline-formula> and <inline-formula><mml:math><mml:mi> μ </mml:mi></mml:math></inline-formula> are constrained by the same bounded vacuum-capacity structure. From Section V.A, the transmissible tension satisfies the universal upper bound</p>
        <disp-formula id="FD42">
          <label>(5.11)</label>
          <mml:math>
            <mml:mrow>
              <mml:mi>T</mml:mi>
              <mml:mo>≤</mml:mo>
              <mml:msub>
                <mml:mi>T</mml:mi>
                <mml:mrow>
                  <mml:mtext>max</mml:mtext>
                </mml:mrow>
              </mml:msub>
              <mml:mo>=</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:msup>
                    <mml:mi>c</mml:mi>
                    <mml:mn>4</mml:mn>
                  </mml:msup>
                </mml:mrow>
                <mml:mi>G</mml:mi>
              </mml:mfrac>
              <mml:mo>,</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>consistent with previously discussed maximum-force bounds in gravitational contexts [<xref ref-type="bibr" rid="B4">4</xref>][<xref ref-type="bibr" rid="B5">5</xref>][<xref ref-type="bibr" rid="B25">25</xref>]. Meanwhile, the effective inertial loading density cannot exceed the maximal vacuum loading per separation derived in Section III, implying</p>
        <disp-formula id="FD43">
          <label>(5.12)</label>
          <mml:math>
            <mml:mrow>
              <mml:mi>μ</mml:mi>
              <mml:mo>≲</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:msup>
                    <mml:mi>c</mml:mi>
                    <mml:mn>2</mml:mn>
                  </mml:msup>
                </mml:mrow>
                <mml:mi>G</mml:mi>
              </mml:mfrac>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>Combining Equations (5.11)-(5.12) yields</p>
        <disp-formula id="FD44">
          <label>(5.13)</label>
          <mml:math>
            <mml:mrow>
              <mml:mfrac>
                <mml:mi>T</mml:mi>
                <mml:mi>μ</mml:mi>
              </mml:mfrac>
              <mml:mo>≤</mml:mo>
              <mml:msup>
                <mml:mi>c</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mo>,</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>and therefore</p>
        <disp-formula id="FD45">
          <label>(5.14)</label>
          <mml:math>
            <mml:mrow>
              <mml:mi>v</mml:mi>
              <mml:mo>≤</mml:mo>
              <mml:mi>c</mml:mi>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>The invariant propagation bound thus follows directly from the finite stiffness-to-inertia ratio permitted by bounded vacuum capacity; no independent kinematic postulate is required. The ratio <inline-formula><mml:math><mml:mrow><mml:mrow><mml:mi> T </mml:mi><mml:mo> / </mml:mo><mml:mi> μ </mml:mi></mml:mrow></mml:mrow></mml:math></inline-formula> sets the intrinsic time scale of vacuum fluctuations, since it fixes the wave speed <inline-formula><mml:math><mml:mrow><mml:mi> v </mml:mi><mml:mo> = </mml:mo><mml:msqrt><mml:mrow><mml:mrow><mml:mi> T </mml:mi><mml:mo> / </mml:mo><mml:mi> μ </mml:mi></mml:mrow></mml:mrow></mml:msqrt></mml:mrow></mml:math></inline-formula> . The equality <inline-formula><mml:math><mml:mrow><mml:mi> v </mml:mi><mml:mo> = </mml:mo><mml:mi> c </mml:mi></mml:mrow></mml:math></inline-formula> corresponds to the intrinsic unsaturated vacuum response for which the effective stiffness-to-inertia ratio attains its fundamental value <inline-formula><mml:math><mml:mrow><mml:mrow><mml:mi> T </mml:mi><mml:mo> / </mml:mo><mml:mi> μ </mml:mi></mml:mrow><mml:mo> = </mml:mo><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:math></inline-formula> . Any additional vacuum loading increases the effective inertial response and thereby reduces the propagation speed below this bound. The massless sector therefore propagates at <inline-formula><mml:math><mml:mi> c </mml:mi></mml:math></inline-formula> , while loaded (massive) configurations exhibit subluminal dynamics.</p>
        <p>This parallels the emergence of characteristic signal speeds in elastic continua and lattice field theories, where propagation velocity is fixed by stiffness-to-inertia ratios [<xref ref-type="bibr" rid="B26">26</xref>]-[<xref ref-type="bibr" rid="B28">28</xref>], while maximum-force bounds have been discussed independently in gravitational settings [<xref ref-type="bibr" rid="B4">4</xref>][<xref ref-type="bibr" rid="B5">5</xref>][<xref ref-type="bibr" rid="B25">25</xref>]. In the bounded-vacuum framework, both force and signal-speed limits arise from the same bounded vacuum-capacity structure. Planck-scale corrections and discrete realizations of this propagation bound are developed in Section VII.</p>
      </sec>
      <sec id="sec5dot3">
        <title>5.3. Lorentz-Invariant Local Propagation</title>
        <p>A crucial property of the bounded-vacuum framework is that gravitational loading modifies the vacuum potential <inline-formula><mml:math><mml:mrow><mml:mtext> Φ </mml:mtext><mml:mrow><mml:mo> ( </mml:mo><mml:mi> x </mml:mi><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> but does not alter the fundamental stiffness-to-inertia ratio governing wave propagation. In the presence of a static vacuum deficit the local energy scale and oscillation frequencies change according to the local potential <inline-formula><mml:math><mml:mrow><mml:mtext> Φ </mml:mtext><mml:mrow><mml:mo> ( </mml:mo><mml:mi> x </mml:mi><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> . However, the parameters <inline-formula><mml:math><mml:mi> T </mml:mi></mml:math></inline-formula> and <inline-formula><mml:math><mml:mi> μ </mml:mi></mml:math></inline-formula> scale proportionally with the local vacuum state, so that their ratio remains constant,</p>
        <disp-formula id="FD46">
          <label>(5.15)</label>
          <mml:math>
            <mml:mrow>
              <mml:mfrac>
                <mml:mi>T</mml:mi>
                <mml:mi>μ</mml:mi>
              </mml:mfrac>
              <mml:mo>=</mml:mo>
              <mml:msup>
                <mml:mi>c</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>Consequently the local propagation speed of disturbances remains</p>
        <disp-formula id="FD47">
          <label>(5.16)</label>
          <mml:math>
            <mml:mrow>
              <mml:mi>v</mml:mi>
              <mml:mo>=</mml:mo>
              <mml:mi>c</mml:mi>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>This invariance of the local signal speed ensures that the effective description of vacuum disturbances is locally Lorentz invariant [<xref ref-type="bibr" rid="B18">18</xref>][<xref ref-type="bibr" rid="B29">29</xref>][<xref ref-type="bibr" rid="B30">30</xref>]. In subsequent sections we show that spatial variations of the vacuum capacity modify the calibration of clocks and rulers while preserving the local propagation speed <inline-formula><mml:math><mml:mi> c </mml:mi></mml:math></inline-formula> . The resulting effective description leads naturally to the emergence of a spacetime metric and relativistic gravitational phenomena.</p>
      </sec>
    </sec>
    <sec id="sec6">
      <title>6. Section VI—Emergent Metric Structure from Vacuum Capacity</title>
      <p>Section V established that disturbances of the vacuum-potential field propagate with an invariant local speed <inline-formula><mml:math><mml:mi> c </mml:mi></mml:math></inline-formula> , determined by the ratio of vacuum transmissible tension to inertial loading density. Although the propagation speed remains invariant, spatial variations of the vacuum capacity modify the intrinsic oscillation frequencies and wavelengths of vacuum-supported modes through the local value of the capacity field <inline-formula><mml:math><mml:mrow><mml:mtext> Φ </mml:mtext><mml:mrow><mml:mo> ( </mml:mo><mml:mi> x </mml:mi><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> . These modifications alter the calibration of clocks and rulers while preserving the local propagation speed <inline-formula><mml:math><mml:mi> c </mml:mi></mml:math></inline-formula> . The resulting description naturally leads to an effective spacetime metric that emerges from spatial variations of the vacuum potential.</p>
      <p>In relativistic quantum theory the energy associated with a particle of inertial mass <inline-formula><mml:math><mml:mi> m </mml:mi></mml:math></inline-formula> is related to frequency through the Planck relation [<xref ref-type="bibr" rid="B31">31</xref>][<xref ref-type="bibr" rid="B32">32</xref>].</p>
      <disp-formula id="FD48">
        <label>(6.1)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>E</mml:mi>
            <mml:mo>=</mml:mo>
            <mml:mi>ℏ</mml:mi>
            <mml:mi>ω</mml:mi>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>Within the bounded-vacuum framework the local energy per unit mass is determined by the vacuum potential, so that the energy of a configuration of mass <inline-formula><mml:math><mml:mi> m </mml:mi></mml:math></inline-formula> embedded in the vacuum field is</p>
      <disp-formula id="FD49">
        <label>(6.2)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>E</mml:mi>
            <mml:mo>=</mml:mo>
            <mml:mi>m</mml:mi>
            <mml:mtext>Φ</mml:mtext>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>x</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>Combining Equations (6.1) and (6.2) gives the intrinsic oscillation frequency</p>
      <disp-formula id="FD50">
        <label>(6.3)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>ω</mml:mi>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>x</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>=</mml:mo>
            <mml:mfrac>
              <mml:mrow>
                <mml:mi>m</mml:mi>
                <mml:mtext>Φ</mml:mtext>
                <mml:mrow>
                  <mml:mo>(</mml:mo>
                  <mml:mi>x</mml:mi>
                  <mml:mo>)</mml:mo>
                </mml:mrow>
              </mml:mrow>
              <mml:mi>ℏ</mml:mi>
            </mml:mfrac>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>Introducing the vacuum-capacity fraction</p>
      <disp-formula id="FD51">
        <label>(6.4)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>f</mml:mi>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>x</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>=</mml:mo>
            <mml:mfrac>
              <mml:mrow>
                <mml:mtext>Φ</mml:mtext>
                <mml:mrow>
                  <mml:mo>(</mml:mo>
                  <mml:mi>x</mml:mi>
                  <mml:mo>)</mml:mo>
                </mml:mrow>
              </mml:mrow>
              <mml:mrow>
                <mml:msup>
                  <mml:mi>c</mml:mi>
                  <mml:mn>2</mml:mn>
                </mml:msup>
              </mml:mrow>
            </mml:mfrac>
            <mml:mo>,</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>the oscillation frequency may be written</p>
      <disp-formula id="FD52">
        <label>(6.5)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>ω</mml:mi>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>x</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>=</mml:mo>
            <mml:msub>
              <mml:mi>ω</mml:mi>
              <mml:mn>0</mml:mn>
            </mml:msub>
            <mml:mi>f</mml:mi>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>x</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>,</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>where</p>
      <disp-formula id="FD53">
        <label>(6.6)</label>
        <mml:math>
          <mml:mrow>
            <mml:msub>
              <mml:mi>ω</mml:mi>
              <mml:mn>0</mml:mn>
            </mml:msub>
            <mml:mo>=</mml:mo>
            <mml:mfrac>
              <mml:mrow>
                <mml:mi>m</mml:mi>
                <mml:msup>
                  <mml:mi>c</mml:mi>
                  <mml:mn>2</mml:mn>
                </mml:msup>
              </mml:mrow>
              <mml:mi>ℏ</mml:mi>
            </mml:mfrac>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>is the intrinsic oscillation frequency in the unloaded vacuum.</p>
      <p>Physical clocks measure time through the phase evolution of periodic processes. If the oscillator phase is denoted by <inline-formula><mml:math><mml:mi> θ </mml:mi></mml:math></inline-formula> , the phase increment may be expressed as</p>
      <disp-formula id="FD54">
        <label>(6.7)</label>
        <mml:math>
          <mml:mrow>
            <mml:mtext>d</mml:mtext>
            <mml:mi>θ</mml:mi>
            <mml:mo>=</mml:mo>
            <mml:mi>ω</mml:mi>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>x</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mtext>
               
            </mml:mtext>
            <mml:mtext>d</mml:mtext>
            <mml:mi>t</mml:mi>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>The same physical phase increment may also be written in terms of the vacuum-reference frequency <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> ω </mml:mi><mml:mn> 0 </mml:mn></mml:msub></mml:mrow></mml:math></inline-formula> and the proper time interval <inline-formula><mml:math><mml:mrow><mml:mtext> d </mml:mtext><mml:mi> τ </mml:mi></mml:mrow></mml:math></inline-formula> ,</p>
      <disp-formula id="FD55">
        <label>(6.8)</label>
        <mml:math>
          <mml:mrow>
            <mml:mtext>d</mml:mtext>
            <mml:mi>θ</mml:mi>
            <mml:mo>=</mml:mo>
            <mml:msub>
              <mml:mi>ω</mml:mi>
              <mml:mn>0</mml:mn>
            </mml:msub>
            <mml:mtext>
               
            </mml:mtext>
            <mml:mtext>d</mml:mtext>
            <mml:mi>τ</mml:mi>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>Equating Equations (6.7) and (6.8), and using Equation (6.5), yields the relation</p>
      <disp-formula id="FD56">
        <label>(6.9)</label>
        <mml:math>
          <mml:mrow>
            <mml:mtext>d</mml:mtext>
            <mml:mi>τ</mml:mi>
            <mml:mo>=</mml:mo>
            <mml:mi>f</mml:mi>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>x</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mtext>
               
            </mml:mtext>
            <mml:mtext>d</mml:mtext>
            <mml:mi>t</mml:mi>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>Thus the rate of proper time relative to coordinate time is determined by the local vacuum-capacity fraction. This relation determines the temporal component of the effective metric,</p>
      <disp-formula id="FD57">
        <label>(6.10)</label>
        <mml:math>
          <mml:mrow>
            <mml:msqrt>
              <mml:mrow>
                <mml:mo>−</mml:mo>
                <mml:msub>
                  <mml:mi>g</mml:mi>
                  <mml:mrow>
                    <mml:mn>00</mml:mn>
                  </mml:mrow>
                </mml:msub>
              </mml:mrow>
            </mml:msqrt>
            <mml:mo>=</mml:mo>
            <mml:mi>f</mml:mi>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>x</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>,</mml:mo>
            <mml:msub>
              <mml:mi>g</mml:mi>
              <mml:mrow>
                <mml:mn>00</mml:mn>
              </mml:mrow>
            </mml:msub>
            <mml:mo>=</mml:mo>
            <mml:mo>−</mml:mo>
            <mml:msup>
              <mml:mi>f</mml:mi>
              <mml:mn>2</mml:mn>
            </mml:msup>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>x</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>Spatial measurements are similarly determined by wave phenomena. For a propagating mode the standard wave relation</p>
      <disp-formula id="FD58">
        <label>(6.11)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>v</mml:mi>
            <mml:mo>=</mml:mo>
            <mml:mfrac>
              <mml:mi>ω</mml:mi>
              <mml:mi>k</mml:mi>
            </mml:mfrac>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>connects frequency and wave number. Section V showed that the propagation speed of disturbances satisfies <inline-formula><mml:math><mml:mrow><mml:mi> v </mml:mi><mml:mo> = </mml:mo><mml:mi> c </mml:mi></mml:mrow></mml:math></inline-formula> . Substituting Equation (6.5) into Equation (6.11) therefore gives</p>
      <disp-formula id="FD59">
        <label>(6.12)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>k</mml:mi>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>x</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>=</mml:mo>
            <mml:mfrac>
              <mml:mrow>
                <mml:mi>ω</mml:mi>
                <mml:mrow>
                  <mml:mo>(</mml:mo>
                  <mml:mi>x</mml:mi>
                  <mml:mo>)</mml:mo>
                </mml:mrow>
              </mml:mrow>
              <mml:mi>c</mml:mi>
            </mml:mfrac>
            <mml:mo>=</mml:mo>
            <mml:msub>
              <mml:mi>k</mml:mi>
              <mml:mn>0</mml:mn>
            </mml:msub>
            <mml:mi>f</mml:mi>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>x</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>,</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>where <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> k </mml:mi><mml:mn> 0 </mml:mn></mml:msub><mml:mo> = </mml:mo><mml:mfrac><mml:mrow><mml:msub><mml:mi> ω </mml:mi><mml:mn> 0 </mml:mn></mml:msub></mml:mrow><mml:mi> c </mml:mi></mml:mfrac></mml:mrow></mml:math></inline-formula> . The corresponding wavelength becomes</p>
      <disp-formula id="FD60">
        <label>(6.13)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>λ</mml:mi>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>x</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>=</mml:mo>
            <mml:mfrac>
              <mml:mrow>
                <mml:mn>2</mml:mn>
                <mml:mi>π</mml:mi>
              </mml:mrow>
              <mml:mrow>
                <mml:mi>k</mml:mi>
                <mml:mrow>
                  <mml:mo>(</mml:mo>
                  <mml:mi>x</mml:mi>
                  <mml:mo>)</mml:mo>
                </mml:mrow>
              </mml:mrow>
            </mml:mfrac>
            <mml:mo>=</mml:mo>
            <mml:mfrac>
              <mml:mrow>
                <mml:msub>
                  <mml:mi>λ</mml:mi>
                  <mml:mn>0</mml:mn>
                </mml:msub>
              </mml:mrow>
              <mml:mrow>
                <mml:mi>f</mml:mi>
                <mml:mrow>
                  <mml:mo>(</mml:mo>
                  <mml:mi>x</mml:mi>
                  <mml:mo>)</mml:mo>
                </mml:mrow>
              </mml:mrow>
            </mml:mfrac>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>Because physical rulers are ultimately defined through microscopic wavelength standards, the locally measured spatial interval scales with the wavelength of vacuum oscillations. The physical spatial element therefore satisfies</p>
      <disp-formula id="FD61">
        <label>(6.14)</label>
        <mml:math>
          <mml:mrow>
            <mml:mtext>d</mml:mtext>
            <mml:msub>
              <mml:mi>l</mml:mi>
              <mml:mrow>
                <mml:mtext>phys</mml:mtext>
              </mml:mrow>
            </mml:msub>
            <mml:mo>∝</mml:mo>
            <mml:mi>λ</mml:mi>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>x</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mtext>
               
            </mml:mtext>
            <mml:mtext>d</mml:mtext>
            <mml:mi>l</mml:mi>
            <mml:mo>∝</mml:mo>
            <mml:mfrac>
              <mml:mn>1</mml:mn>
              <mml:mrow>
                <mml:mi>f</mml:mi>
                <mml:mrow>
                  <mml:mo>(</mml:mo>
                  <mml:mi>x</mml:mi>
                  <mml:mo>)</mml:mo>
                </mml:mrow>
              </mml:mrow>
            </mml:mfrac>
            <mml:mtext>
               
            </mml:mtext>
            <mml:mtext>d</mml:mtext>
            <mml:mi>l</mml:mi>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>This scaling implies that the spatial metric takes the form</p>
      <disp-formula id="FD62">
        <label>(6.15)</label>
        <mml:math>
          <mml:mrow>
            <mml:msub>
              <mml:mi>g</mml:mi>
              <mml:mrow>
                <mml:mi>i</mml:mi>
                <mml:mi>j</mml:mi>
              </mml:mrow>
            </mml:msub>
            <mml:mo>=</mml:mo>
            <mml:msup>
              <mml:mi>f</mml:mi>
              <mml:mrow>
                <mml:mo>−</mml:mo>
                <mml:mn>2</mml:mn>
              </mml:mrow>
            </mml:msup>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>x</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:msub>
              <mml:mi>δ</mml:mi>
              <mml:mrow>
                <mml:mi>i</mml:mi>
                <mml:mi>j</mml:mi>
              </mml:mrow>
            </mml:msub>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>[Or in radial co-ordinate <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> g </mml:mi><mml:mrow><mml:mi> i </mml:mi><mml:mi> j </mml:mi></mml:mrow></mml:msub><mml:mo> = </mml:mo><mml:msup><mml:mi> f </mml:mi><mml:mrow><mml:mo> − </mml:mo><mml:mn> 2 </mml:mn></mml:mrow></mml:msup><mml:mrow><mml:mo> ( </mml:mo><mml:mi> r </mml:mi><mml:mo> ) </mml:mo></mml:mrow><mml:msub><mml:mi> δ </mml:mi><mml:mrow><mml:mi> i </mml:mi><mml:mi> j </mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math></inline-formula> .]</p>
      <p>Combining Equations (6.10) and (6.15) gives the effective spacetime interval</p>
      <disp-formula id="FD63">
        <label>(6.16)</label>
        <mml:math>
          <mml:mrow>
            <mml:mtext>d</mml:mtext>
            <mml:msup>
              <mml:mi>s</mml:mi>
              <mml:mn>2</mml:mn>
            </mml:msup>
            <mml:mo>=</mml:mo>
            <mml:mo>−</mml:mo>
            <mml:msup>
              <mml:mi>f</mml:mi>
              <mml:mn>2</mml:mn>
            </mml:msup>
            <mml:msup>
              <mml:mi>c</mml:mi>
              <mml:mn>2</mml:mn>
            </mml:msup>
            <mml:mtext>d</mml:mtext>
            <mml:msup>
              <mml:mi>t</mml:mi>
              <mml:mn>2</mml:mn>
            </mml:msup>
            <mml:mo>+</mml:mo>
            <mml:msup>
              <mml:mi>f</mml:mi>
              <mml:mrow>
                <mml:mo>−</mml:mo>
                <mml:mn>2</mml:mn>
              </mml:mrow>
            </mml:msup>
            <mml:mtext>d</mml:mtext>
            <mml:msup>
              <mml:mi>l</mml:mi>
              <mml:mn>2</mml:mn>
            </mml:msup>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>For a localized loading <inline-formula><mml:math><mml:mi> M </mml:mi></mml:math></inline-formula> , the static vacuum potential obtained in Section IV, in radial co-ordinate, is</p>
      <disp-formula id="FD64">
        <label>(6.17)</label>
        <mml:math>
          <mml:mrow>
            <mml:mtext>Φ</mml:mtext>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>r</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>=</mml:mo>
            <mml:msup>
              <mml:mi>c</mml:mi>
              <mml:mn>2</mml:mn>
            </mml:msup>
            <mml:mo>−</mml:mo>
            <mml:mfrac>
              <mml:mrow>
                <mml:mi>G</mml:mi>
                <mml:mi>M</mml:mi>
              </mml:mrow>
              <mml:mi>r</mml:mi>
            </mml:mfrac>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>Substituting Equation (6.17) into Equation (6.4) gives</p>
      <disp-formula id="FD65">
        <label>(6.18)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>f</mml:mi>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>r</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>=</mml:mo>
            <mml:mn>1</mml:mn>
            <mml:mo>−</mml:mo>
            <mml:mfrac>
              <mml:mrow>
                <mml:mi>G</mml:mi>
                <mml:mi>M</mml:mi>
              </mml:mrow>
              <mml:mrow>
                <mml:mi>r</mml:mi>
                <mml:msup>
                  <mml:mi>c</mml:mi>
                  <mml:mn>2</mml:mn>
                </mml:msup>
              </mml:mrow>
            </mml:mfrac>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>Expanding Equation (6.16) for weak gravitational loading <inline-formula><mml:math><mml:mrow><mml:mrow><mml:mrow><mml:mi> G </mml:mi><mml:mi> M </mml:mi></mml:mrow><mml:mo> / </mml:mo><mml:mrow><mml:mrow><mml:mo> ( </mml:mo><mml:mrow><mml:mi> r </mml:mi><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:mrow><mml:mo> ≪ </mml:mo><mml:mn> 1 </mml:mn></mml:mrow></mml:math></inline-formula> yields</p>
      <disp-formula id="FD66">
        <label>(6.19)</label>
        <mml:math>
          <mml:mrow>
            <mml:mtext>d</mml:mtext>
            <mml:msup>
              <mml:mi>s</mml:mi>
              <mml:mn>2</mml:mn>
            </mml:msup>
            <mml:mo>=</mml:mo>
            <mml:mo>−</mml:mo>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mrow>
                <mml:mn>1</mml:mn>
                <mml:mo>−</mml:mo>
                <mml:mfrac>
                  <mml:mrow>
                    <mml:mn>2</mml:mn>
                    <mml:mi>G</mml:mi>
                    <mml:mi>M</mml:mi>
                  </mml:mrow>
                  <mml:mrow>
                    <mml:mi>r</mml:mi>
                    <mml:msup>
                      <mml:mi>c</mml:mi>
                      <mml:mn>2</mml:mn>
                    </mml:msup>
                  </mml:mrow>
                </mml:mfrac>
              </mml:mrow>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:msup>
              <mml:mi>c</mml:mi>
              <mml:mn>2</mml:mn>
            </mml:msup>
            <mml:mtext>d</mml:mtext>
            <mml:msup>
              <mml:mi>t</mml:mi>
              <mml:mn>2</mml:mn>
            </mml:msup>
            <mml:mo>+</mml:mo>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mrow>
                <mml:mn>1</mml:mn>
                <mml:mo>+</mml:mo>
                <mml:mfrac>
                  <mml:mrow>
                    <mml:mn>2</mml:mn>
                    <mml:mi>G</mml:mi>
                    <mml:mi>M</mml:mi>
                  </mml:mrow>
                  <mml:mrow>
                    <mml:mi>r</mml:mi>
                    <mml:msup>
                      <mml:mi>c</mml:mi>
                      <mml:mn>2</mml:mn>
                    </mml:msup>
                  </mml:mrow>
                </mml:mfrac>
              </mml:mrow>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mtext>d</mml:mtext>
            <mml:msup>
              <mml:mi>l</mml:mi>
              <mml:mn>2</mml:mn>
            </mml:msup>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>Equation (6.19) coincides with the standard weak-field metric of relativistic gravity [<xref ref-type="bibr" rid="B18">18</xref>][<xref ref-type="bibr" rid="B29">29</xref>][<xref ref-type="bibr" rid="B30">30</xref>]. In the bounded-vacuum interpretation this metric does not arise from a fundamental geometric postulate but from the response of the vacuum capacity to matter loading. The same capacity fraction <inline-formula><mml:math><mml:mrow><mml:mi> f </mml:mi><mml:mrow><mml:mo> ( </mml:mo><mml:mi> x </mml:mi><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> simultaneously governs the calibration of clocks and rulers through its influence on intrinsic oscillation frequencies and wavelengths.</p>
      <p>Thus spacetime curvature appears as the macroscopic geometric description of spatial variations in the vacuum capacity field <inline-formula><mml:math><mml:mrow><mml:mtext> Φ </mml:mtext><mml:mrow><mml:mo> ( </mml:mo><mml:mi> x </mml:mi><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> . Regions where <inline-formula><mml:math><mml:mrow><mml:mo> ∇ </mml:mo><mml:mtext> Φ </mml:mtext><mml:mo> ≠ </mml:mo><mml:mn> 0 </mml:mn></mml:mrow></mml:math></inline-formula> correspond to gradients in the vacuum capacity that modify both temporal and spatial measurement standards. In this way the gravitational field emerges as an effective manifestation of the finite and redistributable capacity of the physical vacuum.</p>
    </sec>
    <sec id="sec7">
      <title>7. Section VII—Action Quantization as a Vacuum Capacity Constraint and the Emergent Planck Scale</title>
      <p>Quantum dynamics is governed by the action functional</p>
      <disp-formula id="FD67">
        <label>(7.1)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>S</mml:mi>
            <mml:mo>=</mml:mo>
            <mml:mstyle displaystyle="true">
              <mml:mrow>
                <mml:mo>∫</mml:mo>
                <mml:mrow>
                  <mml:mi>L</mml:mi>
                  <mml:mtext>
                     
                  </mml:mtext>
                  <mml:mtext>d</mml:mtext>
                  <mml:mi>t</mml:mi>
                </mml:mrow>
              </mml:mrow>
            </mml:mstyle>
            <mml:mo>,</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>which enters transition amplitudes through the phase factor <inline-formula><mml:math><mml:mrow><mml:msup><mml:mtext> e </mml:mtext><mml:mrow><mml:mi> i </mml:mi><mml:mi> S </mml:mi><mml:mo> / </mml:mo><mml:mi> ℏ </mml:mi></mml:mrow></mml:msup></mml:mrow></mml:math></inline-formula> [<xref ref-type="bibr" rid="B33">33</xref>][<xref ref-type="bibr" rid="B34">34</xref>]. Physical distinguishability arises only when variations in the action satisfy</p>
      <disp-formula id="FD68">
        <label>(7.2)</label>
        <mml:math>
          <mml:mrow>
            <mml:mtext>Δ</mml:mtext>
            <mml:mi>S</mml:mi>
            <mml:mo>∼</mml:mo>
            <mml:mi>ℏ</mml:mi>
            <mml:mo>,</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>so that <inline-formula><mml:math><mml:mi> ℏ </mml:mi></mml:math></inline-formula> defines the fundamental quantum of action [<xref ref-type="bibr" rid="B35">35</xref>]. Equation (7.2) introduces neither the gravitational constant <inline-formula><mml:math><mml:mi> G </mml:mi></mml:math></inline-formula> nor an intrinsic length scale. In the bounded-vacuum framework established in Sections II-V, the vacuum possesses a maximal potential reference level</p>
      <disp-formula id="FD69">
        <mml:math>
          <mml:mrow>
            <mml:msub>
              <mml:mtext>Φ</mml:mtext>
              <mml:mn>0</mml:mn>
            </mml:msub>
            <mml:mo>=</mml:mo>
            <mml:msup>
              <mml:mi>c</mml:mi>
              <mml:mn>2</mml:mn>
            </mml:msup>
            <mml:mo>,</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>fixed by relativistic normalization. A localized vacuum loading <inline-formula><mml:math><mml:mi> m </mml:mi></mml:math></inline-formula> therefore carries a characteristic energy</p>
      <disp-formula id="FD70">
        <label>(7.3)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>E</mml:mi>
            <mml:mo>=</mml:mo>
            <mml:mi>m</mml:mi>
            <mml:msup>
              <mml:mi>c</mml:mi>
              <mml:mn>2</mml:mn>
            </mml:msup>
            <mml:mo>,</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>as follows directly from the definition of vacuum loading in Section III.</p>
      <p>Over a time interval <inline-formula><mml:math><mml:mrow><mml:mtext> Δ </mml:mtext><mml:mi> t </mml:mi></mml:mrow></mml:math></inline-formula> , the action associated with this redistribution is</p>
      <disp-formula id="FD71">
        <label>(7.4)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>S</mml:mi>
            <mml:mo>=</mml:mo>
            <mml:mi>E</mml:mi>
            <mml:mtext>
               
            </mml:mtext>
            <mml:mtext>Δ</mml:mtext>
            <mml:mi>t</mml:mi>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>Imposing the minimal quantum condition (6.2) gives</p>
      <disp-formula id="FD72">
        <label>(7.5)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>E</mml:mi>
            <mml:mtext>
               
            </mml:mtext>
            <mml:mtext>Δ</mml:mtext>
            <mml:mi>t</mml:mi>
            <mml:mo>=</mml:mo>
            <mml:mi>ℏ</mml:mi>
            <mml:mo>,</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>or</p>
      <disp-formula id="FD73">
        <label>(7.6)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>m</mml:mi>
            <mml:msup>
              <mml:mi>c</mml:mi>
              <mml:mn>2</mml:mn>
            </mml:msup>
            <mml:mtext>Δ</mml:mtext>
            <mml:mi>t</mml:mi>
            <mml:mo>=</mml:mo>
            <mml:mi>ℏ</mml:mi>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>Because redistribution of the vacuum field cannot propagate faster than the universal bound <inline-formula><mml:math><mml:mi> c </mml:mi></mml:math></inline-formula> established in Section V, the associated spatial scale <inline-formula><mml:math><mml:mi> λ </mml:mi></mml:math></inline-formula> satisfies</p>
      <disp-formula id="FD74">
        <label>(7.7)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>λ</mml:mi>
            <mml:mo>=</mml:mo>
            <mml:mi>c</mml:mi>
            <mml:mtext>
               
            </mml:mtext>
            <mml:mtext>Δ</mml:mtext>
            <mml:mi>t</mml:mi>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>Combining Equations (7.6)-(7.7) yields</p>
      <disp-formula id="FD75">
        <label>(7.8)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>m</mml:mi>
            <mml:mi>c</mml:mi>
            <mml:mi>λ</mml:mi>
            <mml:mo>=</mml:mo>
            <mml:mi>ℏ</mml:mi>
            <mml:mo>,</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>or equivalently,</p>
      <disp-formula id="FD76">
        <label>(7.9)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>λ</mml:mi>
            <mml:mo>=</mml:mo>
            <mml:mfrac>
              <mml:mi>ℏ</mml:mi>
              <mml:mrow>
                <mml:mi>m</mml:mi>
                <mml:mi>c</mml:mi>
              </mml:mrow>
            </mml:mfrac>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>Equation (7.9) expresses a property of the vacuum medium: quantum action quantization enforces an inverse relation between vacuum loading <inline-formula><mml:math><mml:mi> m </mml:mi></mml:math></inline-formula> and the spatial scale <inline-formula><mml:math><mml:mi> λ </mml:mi></mml:math></inline-formula> over which redistribution occurs. No minimal length follows from quantum action alone, since both <inline-formula><mml:math><mml:mi> m </mml:mi></mml:math></inline-formula> and <inline-formula><mml:math><mml:mi> λ </mml:mi></mml:math></inline-formula> remain continuous.</p>
      <p>Gravitational coupling introduces an independent localization constraint derived in Section III. Finite vacuum capacity implies a collapse radius</p>
      <disp-formula id="FD77">
        <label>(7.10)</label>
        <mml:math>
          <mml:mrow>
            <mml:msub>
              <mml:mi>r</mml:mi>
              <mml:mi>c</mml:mi>
            </mml:msub>
            <mml:mo>∼</mml:mo>
            <mml:mfrac>
              <mml:mrow>
                <mml:mi>G</mml:mi>
                <mml:mi>m</mml:mi>
              </mml:mrow>
              <mml:mrow>
                <mml:msup>
                  <mml:mi>c</mml:mi>
                  <mml:mn>2</mml:mn>
                </mml:msup>
              </mml:mrow>
            </mml:mfrac>
            <mml:mo>,</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>which represents the maximal concentration of loading consistent with capacity saturation [<xref ref-type="bibr" rid="B2">2</xref>].</p>
      <p>Self-consistency requires that quantum localization not exceed the gravitational saturation scale,</p>
      <disp-formula id="FD78">
        <label>(7.11)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>λ</mml:mi>
            <mml:mo>≳</mml:mo>
            <mml:msub>
              <mml:mi>r</mml:mi>
              <mml:mi>c</mml:mi>
            </mml:msub>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>At the threshold of simultaneous quantum and gravitational saturation, setting</p>
      <disp-formula id="FD79">
        <label>(7.12)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>λ</mml:mi>
            <mml:mo>=</mml:mo>
            <mml:msub>
              <mml:mi>r</mml:mi>
              <mml:mi>c</mml:mi>
            </mml:msub>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>and substituting Equations (7.9) and (7.10) gives</p>
      <disp-formula id="FD80">
        <label>(7.13)</label>
        <mml:math>
          <mml:mrow>
            <mml:mfrac>
              <mml:mi>ℏ</mml:mi>
              <mml:mrow>
                <mml:mi>m</mml:mi>
                <mml:mi>c</mml:mi>
              </mml:mrow>
            </mml:mfrac>
            <mml:mo>=</mml:mo>
            <mml:mfrac>
              <mml:mrow>
                <mml:mi>G</mml:mi>
                <mml:mi>m</mml:mi>
              </mml:mrow>
              <mml:mrow>
                <mml:msup>
                  <mml:mi>c</mml:mi>
                  <mml:mn>2</mml:mn>
                </mml:msup>
              </mml:mrow>
            </mml:mfrac>
            <mml:mo>,</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>which implies</p>
      <disp-formula id="FD81">
        <label>(7.14)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>G</mml:mi>
            <mml:msup>
              <mml:mi>m</mml:mi>
              <mml:mn>2</mml:mn>
            </mml:msup>
            <mml:mo>=</mml:mo>
            <mml:mi>ℏ</mml:mi>
            <mml:mi>c</mml:mi>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>The critical loading is therefore</p>
      <disp-formula id="FD82">
        <label>(7.15)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>m</mml:mi>
            <mml:mo>=</mml:mo>
            <mml:msqrt>
              <mml:mrow>
                <mml:mfrac>
                  <mml:mrow>
                    <mml:mi>ℏ</mml:mi>
                    <mml:mi>c</mml:mi>
                  </mml:mrow>
                  <mml:mi>G</mml:mi>
                </mml:mfrac>
              </mml:mrow>
            </mml:msqrt>
            <mml:mo>≡</mml:mo>
            <mml:msub>
              <mml:mi>m</mml:mi>
              <mml:mi>P</mml:mi>
            </mml:msub>
            <mml:mo>,</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>and the corresponding localization scale becomes</p>
      <disp-formula id="FD83">
        <label>(7.16)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>λ</mml:mi>
            <mml:mo>=</mml:mo>
            <mml:msub>
              <mml:mi>r</mml:mi>
              <mml:mi>c</mml:mi>
            </mml:msub>
            <mml:mo>=</mml:mo>
            <mml:msqrt>
              <mml:mrow>
                <mml:mfrac>
                  <mml:mrow>
                    <mml:mi>ℏ</mml:mi>
                    <mml:mi>G</mml:mi>
                  </mml:mrow>
                  <mml:mrow>
                    <mml:msup>
                      <mml:mi>c</mml:mi>
                      <mml:mn>3</mml:mn>
                    </mml:msup>
                  </mml:mrow>
                </mml:mfrac>
              </mml:mrow>
            </mml:msqrt>
            <mml:mo>≡</mml:mo>
            <mml:msub>
              <mml:mi>ℓ</mml:mi>
              <mml:mi>P</mml:mi>
            </mml:msub>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>The Planck scale thus emerges as the unique intersection of two independent vacuum-capacity constraints:</p>
      <p>1) quantum action quantization (<inline-formula><mml:math><mml:mi> ℏ </mml:mi></mml:math></inline-formula> ),</p>
      <p>2) gravitational loading consistency (<inline-formula><mml:math><mml:mi> G </mml:mi></mml:math></inline-formula> ),</p>
      <p>Both referenced to the invariant vacuum potential scale <inline-formula><mml:math><mml:mrow><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:math></inline-formula> .</p>
      <p>So, the Planck length <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> ℓ </mml:mi><mml:mi> P </mml:mi></mml:msub></mml:mrow></mml:math></inline-formula> arises as the saturation boundary of the vacuum medium at which quantum redistribution and gravitational capacity simultaneously reach their limiting values. At scales smaller than <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> ℓ </mml:mi><mml:mi> P </mml:mi></mml:msub></mml:mrow></mml:math></inline-formula> , the vacuum cannot consistently satisfy both constraints within the continuum description.</p>
    </sec>
    <sec id="sec8">
      <title>8. Section VIII—Dispersion, Universality, and Observational Consistency</title>
      <p>Sections II-VI established that the vacuum-potential field <inline-formula><mml:math><mml:mrow><mml:mtext> Φ </mml:mtext><mml:mrow><mml:mo> ( </mml:mo><mml:mrow><mml:mi> x </mml:mi><mml:mo> , </mml:mo><mml:mi> t </mml:mi></mml:mrow><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> possesses finite capacity <inline-formula><mml:math><mml:mrow><mml:mtext> Φ </mml:mtext><mml:mo> ≤ </mml:mo><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:math></inline-formula> , supports static relaxation profiles, and admits dynamical propagation with a universal signal-speed bound <inline-formula><mml:math><mml:mrow><mml:mi> v </mml:mi><mml:mo> ≤ </mml:mo><mml:mi> c </mml:mi></mml:mrow></mml:math></inline-formula> . We now examine the ultraviolet structure implied by the existence of a minimal response scale. Rather than postulating fundamental discreteness as an axiom, we adopt the minimal microscopic realization compatible with bounded gradients and maximum transmissible tension: a scalar field defined on a lattice of spacing <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> ℓ </mml:mi><mml:mo> * </mml:mo></mml:msub></mml:mrow></mml:math></inline-formula> . Such discretizations are standard in lattice quantum field theory and in condensed-matter systems, where continuum behavior emerges at long wavelengths while ultraviolet modes are regulated by the underlying spacing [<xref ref-type="bibr" rid="B8">8</xref>][<xref ref-type="bibr" rid="B9">9</xref>][<xref ref-type="bibr" rid="B26">26</xref>].</p>
      <p>Let <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> ϕ </mml:mi><mml:mi> n </mml:mi></mml:msub><mml:mrow><mml:mo> ( </mml:mo><mml:mi> t </mml:mi><mml:mo> ) </mml:mo></mml:mrow><mml:mo> ≡ </mml:mo><mml:msub><mml:mtext> Φ </mml:mtext><mml:mi> n </mml:mi></mml:msub><mml:mrow><mml:mo> ( </mml:mo><mml:mi> t </mml:mi><mml:mo> ) </mml:mo></mml:mrow><mml:mo> − </mml:mo><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:math></inline-formula> denote small deviations from equilibrium at lattice site <inline-formula><mml:math><mml:mi> n </mml:mi></mml:math></inline-formula> . For a one-dimensional chain with nearest-neighbor coupling consistent with the continuum action of Section V, small-amplitude disturbances satisfy the discrete equation</p>
      <disp-formula id="FD84">
        <label>(8.1)</label>
        <mml:math>
          <mml:mrow>
            <mml:msub>
              <mml:mover accent="true">
                <mml:mi>ϕ</mml:mi>
                <mml:mo>¨</mml:mo>
              </mml:mover>
              <mml:mi>n</mml:mi>
            </mml:msub>
            <mml:mo>=</mml:mo>
            <mml:mfrac>
              <mml:mrow>
                <mml:msup>
                  <mml:mi>c</mml:mi>
                  <mml:mn>2</mml:mn>
                </mml:msup>
              </mml:mrow>
              <mml:mrow>
                <mml:msubsup>
                  <mml:mi>ℓ</mml:mi>
                  <mml:mo>*</mml:mo>
                  <mml:mn>2</mml:mn>
                </mml:msubsup>
              </mml:mrow>
            </mml:mfrac>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mrow>
                <mml:msub>
                  <mml:mi>ϕ</mml:mi>
                  <mml:mrow>
                    <mml:mi>n</mml:mi>
                    <mml:mo>+</mml:mo>
                    <mml:mn>1</mml:mn>
                  </mml:mrow>
                </mml:msub>
                <mml:mo>−</mml:mo>
                <mml:mn>2</mml:mn>
                <mml:msub>
                  <mml:mi>ϕ</mml:mi>
                  <mml:mi>n</mml:mi>
                </mml:msub>
                <mml:mo>+</mml:mo>
                <mml:msub>
                  <mml:mi>ϕ</mml:mi>
                  <mml:mrow>
                    <mml:mi>n</mml:mi>
                    <mml:mo>−</mml:mo>
                    <mml:mn>1</mml:mn>
                  </mml:mrow>
                </mml:msub>
              </mml:mrow>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>which reduces to the continuum wave equation in the long-wavelength limit <inline-formula><mml:math><mml:mrow><mml:mi> k </mml:mi><mml:msub><mml:mi> ℓ </mml:mi><mml:mo> * </mml:mo></mml:msub><mml:mo> ≪ </mml:mo><mml:mn> 1 </mml:mn></mml:mrow></mml:math></inline-formula> .</p>
      <p>Seeking plane-wave solutions</p>
      <disp-formula id="FD85">
        <label>(8.2)</label>
        <mml:math>
          <mml:mrow>
            <mml:msub>
              <mml:mi>ϕ</mml:mi>
              <mml:mi>n</mml:mi>
            </mml:msub>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>t</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>=</mml:mo>
            <mml:msup>
              <mml:mtext>e</mml:mtext>
              <mml:mrow>
                <mml:mi>i</mml:mi>
                <mml:mrow>
                  <mml:mo>(</mml:mo>
                  <mml:mrow>
                    <mml:mi>k</mml:mi>
                    <mml:mi>n</mml:mi>
                    <mml:msub>
                      <mml:mi>ℓ</mml:mi>
                      <mml:mo>*</mml:mo>
                    </mml:msub>
                    <mml:mo>−</mml:mo>
                    <mml:mi>ω</mml:mi>
                    <mml:mi>t</mml:mi>
                  </mml:mrow>
                  <mml:mo>)</mml:mo>
                </mml:mrow>
              </mml:mrow>
            </mml:msup>
            <mml:mo>,</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>yields the exact lattice dispersion relation</p>
      <disp-formula id="FD86">
        <label>(8.3)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>ω</mml:mi>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>k</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>=</mml:mo>
            <mml:mfrac>
              <mml:mrow>
                <mml:mn>2</mml:mn>
                <mml:mi>c</mml:mi>
              </mml:mrow>
              <mml:mrow>
                <mml:msub>
                  <mml:mi>ℓ</mml:mi>
                  <mml:mo>*</mml:mo>
                </mml:msub>
              </mml:mrow>
            </mml:mfrac>
            <mml:mtext>sin</mml:mtext>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mrow>
                <mml:mfrac>
                  <mml:mrow>
                    <mml:mi>k</mml:mi>
                    <mml:msub>
                      <mml:mi>ℓ</mml:mi>
                      <mml:mo>*</mml:mo>
                    </mml:msub>
                  </mml:mrow>
                  <mml:mn>2</mml:mn>
                </mml:mfrac>
              </mml:mrow>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>,</mml:mo>
            <mml:mrow>
              <mml:mo>|</mml:mo>
              <mml:mi>k</mml:mi>
              <mml:mo>|</mml:mo>
            </mml:mrow>
            <mml:mo>≤</mml:mo>
            <mml:mfrac>
              <mml:mi>π</mml:mi>
              <mml:mrow>
                <mml:msub>
                  <mml:mi>ℓ</mml:mi>
                  <mml:mo>*</mml:mo>
                </mml:msub>
              </mml:mrow>
            </mml:mfrac>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>The corresponding group velocity is</p>
      <disp-formula id="FD87">
        <label>(8.4)</label>
        <mml:math display="inline">
          <mml:mrow>
            <mml:msub>
              <mml:mi>v</mml:mi>
              <mml:mi>g</mml:mi>
            </mml:msub>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>k</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>=</mml:mo>
            <mml:mfrac>
              <mml:mrow>
                <mml:mtext>d</mml:mtext>
                <mml:mi>ω</mml:mi>
              </mml:mrow>
              <mml:mrow>
                <mml:mtext>d</mml:mtext>
                <mml:mi>k</mml:mi>
              </mml:mrow>
            </mml:mfrac>
            <mml:mo>=</mml:mo>
            <mml:mi>c</mml:mi>
            <mml:mtext>cos</mml:mtext>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mrow>
                <mml:mfrac>
                  <mml:mrow>
                    <mml:mi>k</mml:mi>
                    <mml:msub>
                      <mml:mi>ℓ</mml:mi>
                      <mml:mo>*</mml:mo>
                    </mml:msub>
                  </mml:mrow>
                  <mml:mn>2</mml:mn>
                </mml:mfrac>
              </mml:mrow>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>,</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>which satisfies <inline-formula><mml:math><mml:mrow><mml:mn> 0 </mml:mn><mml:mo> ≤ </mml:mo><mml:msub><mml:mi> v </mml:mi><mml:mi> g </mml:mi></mml:msub><mml:mo> ≤ </mml:mo><mml:mi> c </mml:mi></mml:mrow></mml:math></inline-formula> for all modes. Thus the universal speed bound derived in Section V is automatically preserved in the microscopic realization. Causality is enforced dynamically by finite vacuum transmissibility rather than imposed kinematically, consistent with maximum-force arguments [<xref ref-type="bibr" rid="B4">4</xref>]-[<xref ref-type="bibr" rid="B6">6</xref>].</p>
      <p>In the long-wavelength limit <inline-formula><mml:math><mml:mrow><mml:mi> k </mml:mi><mml:msub><mml:mi> ℓ </mml:mi><mml:mo> * </mml:mo></mml:msub><mml:mo> ≪ </mml:mo><mml:mn> 1 </mml:mn></mml:mrow></mml:math></inline-formula> , expanding Equation (8.3) gives</p>
      <disp-formula id="FD88">
        <label>(8.5)</label>
        <mml:math>
          <mml:mrow>
            <mml:mi>ω</mml:mi>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>k</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>=</mml:mo>
            <mml:mi>c</mml:mi>
            <mml:mi>k</mml:mi>
            <mml:mrow>
              <mml:mo>[</mml:mo>
              <mml:mrow>
                <mml:mn>1</mml:mn>
                <mml:mo>−</mml:mo>
                <mml:mfrac>
                  <mml:mrow>
                    <mml:msup>
                      <mml:mrow>
                        <mml:mrow>
                          <mml:mo>(</mml:mo>
                          <mml:mrow>
                            <mml:mi>k</mml:mi>
                            <mml:msub>
                              <mml:mi>ℓ</mml:mi>
                              <mml:mo>*</mml:mo>
                            </mml:msub>
                          </mml:mrow>
                          <mml:mo>)</mml:mo>
                        </mml:mrow>
                      </mml:mrow>
                      <mml:mn>2</mml:mn>
                    </mml:msup>
                  </mml:mrow>
                  <mml:mrow>
                    <mml:mn>24</mml:mn>
                  </mml:mrow>
                </mml:mfrac>
                <mml:mo>+</mml:mo>
                <mml:mi mathvariant="script">O</mml:mi>
                <mml:mrow>
                  <mml:mo>(</mml:mo>
                  <mml:mrow>
                    <mml:msup>
                      <mml:mrow>
                        <mml:mrow>
                          <mml:mo>(</mml:mo>
                          <mml:mrow>
                            <mml:mi>k</mml:mi>
                            <mml:msub>
                              <mml:mi>ℓ</mml:mi>
                              <mml:mo>*</mml:mo>
                            </mml:msub>
                          </mml:mrow>
                          <mml:mo>)</mml:mo>
                        </mml:mrow>
                      </mml:mrow>
                      <mml:mn>4</mml:mn>
                    </mml:msup>
                  </mml:mrow>
                  <mml:mo>)</mml:mo>
                </mml:mrow>
              </mml:mrow>
              <mml:mo>]</mml:mo>
            </mml:mrow>
            <mml:mo>,</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>and therefore</p>
      <disp-formula id="FD89">
        <label>(8.6)</label>
        <mml:math>
          <mml:mrow>
            <mml:msub>
              <mml:mi>v</mml:mi>
              <mml:mi>g</mml:mi>
            </mml:msub>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>k</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>=</mml:mo>
            <mml:mi>c</mml:mi>
            <mml:mrow>
              <mml:mo>[</mml:mo>
              <mml:mrow>
                <mml:mn>1</mml:mn>
                <mml:mo>−</mml:mo>
                <mml:mfrac>
                  <mml:mrow>
                    <mml:msup>
                      <mml:mrow>
                        <mml:mrow>
                          <mml:mo>(</mml:mo>
                          <mml:mrow>
                            <mml:mi>k</mml:mi>
                            <mml:msub>
                              <mml:mi>ℓ</mml:mi>
                              <mml:mo>*</mml:mo>
                            </mml:msub>
                          </mml:mrow>
                          <mml:mo>)</mml:mo>
                        </mml:mrow>
                      </mml:mrow>
                      <mml:mn>2</mml:mn>
                    </mml:msup>
                  </mml:mrow>
                  <mml:mn>8</mml:mn>
                </mml:mfrac>
                <mml:mo>+</mml:mo>
                <mml:mi mathvariant="script">O</mml:mi>
                <mml:mrow>
                  <mml:mo>(</mml:mo>
                  <mml:mrow>
                    <mml:msup>
                      <mml:mrow>
                        <mml:mrow>
                          <mml:mo>(</mml:mo>
                          <mml:mrow>
                            <mml:mi>k</mml:mi>
                            <mml:msub>
                              <mml:mi>ℓ</mml:mi>
                              <mml:mo>*</mml:mo>
                            </mml:msub>
                          </mml:mrow>
                          <mml:mo>)</mml:mo>
                        </mml:mrow>
                      </mml:mrow>
                      <mml:mn>4</mml:mn>
                    </mml:msup>
                  </mml:mrow>
                  <mml:mo>)</mml:mo>
                </mml:mrow>
              </mml:mrow>
              <mml:mo>]</mml:mo>
            </mml:mrow>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>Relativistic dispersion is thus recovered universally at low energies, while deviations are quadratic and suppressed by the microscopic scale <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> ℓ </mml:mi><mml:mo> * </mml:mo></mml:msub></mml:mrow></mml:math></inline-formula> . The absence of linear corrections follows directly from parity symmetry of the discrete Laplacian and does not require additional symmetry assumptions [<xref ref-type="bibr" rid="B8">8</xref>][<xref ref-type="bibr" rid="B26">26</xref>].</p>
      <p>Using the standard identifications</p>
      <disp-formula id="FD90">
        <mml:math>
          <mml:mrow>
            <mml:mi>E</mml:mi>
            <mml:mo>=</mml:mo>
            <mml:mi>ℏ</mml:mi>
            <mml:mi>ω</mml:mi>
            <mml:mo>,</mml:mo>
            <mml:mi>p</mml:mi>
            <mml:mo>=</mml:mo>
            <mml:mi>ℏ</mml:mi>
            <mml:mi>k</mml:mi>
            <mml:mo>,</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>and defining the characteristic energy scale</p>
      <disp-formula id="FD91">
        <label>(8.7)</label>
        <mml:math>
          <mml:mrow>
            <mml:msub>
              <mml:mi>E</mml:mi>
              <mml:mo>*</mml:mo>
            </mml:msub>
            <mml:mo>=</mml:mo>
            <mml:mfrac>
              <mml:mrow>
                <mml:mi>ℏ</mml:mi>
                <mml:mi>c</mml:mi>
              </mml:mrow>
              <mml:mrow>
                <mml:msub>
                  <mml:mi>ℓ</mml:mi>
                  <mml:mo>*</mml:mo>
                </mml:msub>
              </mml:mrow>
            </mml:mfrac>
            <mml:mo>,</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>the fractional velocity deviation becomes</p>
      <disp-formula id="FD92">
        <label>(8.8)</label>
        <mml:math>
          <mml:mrow>
            <mml:mfrac>
              <mml:mrow>
                <mml:mtext>Δ</mml:mtext>
                <mml:mi>v</mml:mi>
              </mml:mrow>
              <mml:mi>c</mml:mi>
            </mml:mfrac>
            <mml:mo>≡</mml:mo>
            <mml:mfrac>
              <mml:mrow>
                <mml:msub>
                  <mml:mi>v</mml:mi>
                  <mml:mi>g</mml:mi>
                </mml:msub>
                <mml:mo>−</mml:mo>
                <mml:mi>c</mml:mi>
              </mml:mrow>
              <mml:mi>c</mml:mi>
            </mml:mfrac>
            <mml:mo>≃</mml:mo>
            <mml:mo>−</mml:mo>
            <mml:mfrac>
              <mml:mn>1</mml:mn>
              <mml:mn>8</mml:mn>
            </mml:mfrac>
            <mml:msup>
              <mml:mrow>
                <mml:mrow>
                  <mml:mo>(</mml:mo>
                  <mml:mrow>
                    <mml:mfrac>
                      <mml:mi>E</mml:mi>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>E</mml:mi>
                          <mml:mo>*</mml:mo>
                        </mml:msub>
                      </mml:mrow>
                    </mml:mfrac>
                  </mml:mrow>
                  <mml:mo>)</mml:mo>
                </mml:mrow>
              </mml:mrow>
              <mml:mn>2</mml:mn>
            </mml:msup>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>From Section VI, simultaneous quantum and gravitational saturation uniquely fixed the minimal response scale to be</p>
      <disp-formula id="FD93">
        <label>(8.9)</label>
        <mml:math>
          <mml:mrow>
            <mml:msub>
              <mml:mi>ℓ</mml:mi>
              <mml:mo>*</mml:mo>
            </mml:msub>
            <mml:mo>=</mml:mo>
            <mml:msub>
              <mml:mi>ℓ</mml:mi>
              <mml:mi>P</mml:mi>
            </mml:msub>
            <mml:mo>=</mml:mo>
            <mml:msqrt>
              <mml:mrow>
                <mml:mfrac>
                  <mml:mrow>
                    <mml:mi>ℏ</mml:mi>
                    <mml:mi>G</mml:mi>
                  </mml:mrow>
                  <mml:mrow>
                    <mml:msup>
                      <mml:mi>c</mml:mi>
                      <mml:mn>3</mml:mn>
                    </mml:msup>
                  </mml:mrow>
                </mml:mfrac>
              </mml:mrow>
            </mml:msqrt>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>The corresponding energy scale becomes the Planck energy,</p>
      <disp-formula id="FD94">
        <label>(8.10)</label>
        <mml:math>
          <mml:mrow>
            <mml:msub>
              <mml:mi>E</mml:mi>
              <mml:mi>P</mml:mi>
            </mml:msub>
            <mml:mo>=</mml:mo>
            <mml:mfrac>
              <mml:mrow>
                <mml:mi>ℏ</mml:mi>
                <mml:mi>c</mml:mi>
              </mml:mrow>
              <mml:mrow>
                <mml:msub>
                  <mml:mi>ℓ</mml:mi>
                  <mml:mi>P</mml:mi>
                </mml:msub>
              </mml:mrow>
            </mml:mfrac>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>Substituting Equation (8.9) into Equation (8.8) yields the parameter-free prediction</p>
      <disp-formula id="FD95">
        <label>(8.11)</label>
        <mml:math>
          <mml:mrow>
            <mml:mfrac>
              <mml:mrow>
                <mml:mtext>Δ</mml:mtext>
                <mml:mi>v</mml:mi>
              </mml:mrow>
              <mml:mi>c</mml:mi>
            </mml:mfrac>
            <mml:mo>≃</mml:mo>
            <mml:mo>−</mml:mo>
            <mml:mfrac>
              <mml:mn>1</mml:mn>
              <mml:mn>8</mml:mn>
            </mml:mfrac>
            <mml:msup>
              <mml:mrow>
                <mml:mrow>
                  <mml:mo>(</mml:mo>
                  <mml:mrow>
                    <mml:mfrac>
                      <mml:mi>E</mml:mi>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>E</mml:mi>
                          <mml:mi>P</mml:mi>
                        </mml:msub>
                      </mml:mrow>
                    </mml:mfrac>
                  </mml:mrow>
                  <mml:mo>)</mml:mo>
                </mml:mrow>
              </mml:mrow>
              <mml:mn>2</mml:mn>
            </mml:msup>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>This quadratic, Planck-suppressed correction follows directly from bounded vacuum transmissibility and the minimal response scale derived in Section VI. The associated microscopic structure motivates the designation Dynamical Planck Network (DPN) for the underlying vacuum description. The correction depends only on energy and the fundamental constants <inline-formula><mml:math><mml:mrow><mml:mi> ℏ </mml:mi><mml:mo> , </mml:mo><mml:mi> c </mml:mi><mml:mo> , </mml:mo><mml:mi> G </mml:mi></mml:mrow></mml:math></inline-formula> , and is independent of particle species or interaction details. Similar infrared universality with ultraviolet lattice corrections appears in emergent-spacetime and analogue-gravity models [<xref ref-type="bibr" rid="B10">10</xref>][<xref ref-type="bibr" rid="B23">23</xref>].</p>
      <p>Observationally, high-energy astrophysical measurements place stringent bounds on leading-order (linear-in-energy) Lorentz-violating dispersion [<xref ref-type="bibr" rid="B36">36</xref>]-[<xref ref-type="bibr" rid="B38">38</xref>]. The present framework automatically satisfies these constraints because 1) no linear term arises in the dispersion relation and 2) the leading modification is quadratic and suppressed by the Planck scale <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> E </mml:mi><mml:mi> P </mml:mi></mml:msub></mml:mrow></mml:math></inline-formula> [<xref ref-type="bibr" rid="B36">36</xref>]-[<xref ref-type="bibr" rid="B38">38</xref>]. Gravitational-wave observations likewise constrain deviations from luminal propagation [<xref ref-type="bibr" rid="B39">39</xref>]; quadratic, Planck-suppressed corrections of the form (8.11) remain well within current experimental limits.</p>
      <p>The framework remains falsifiable. Any robust detection of linear dispersion, anisotropic propagation, or species-dependent velocity corrections would contradict the minimal symmetric vacuum model developed here.</p>
      <p>In summary, once finite vacuum capacity and a minimal response scale are admitted, relativistic propagation emerges as a universal infrared limit, while Planck-suppressed quadratic dispersion arises as a controlled ultraviolet correction. The structure mirrors that of symmetric lattice field systems, yet here it follows from bounded vacuum transmissibility rather than from an imposed spacetime background.</p>
    </sec>
    <sec id="sec9">
      <title>9. Section IX—Physical Implications and Mathematical Consequences of the Bounded-Vacuum Framework</title>
      <p>Sections II-VIII established that the bounded-vacuum framework is governed by a single scalar vacuum-potential field <inline-formula><mml:math><mml:mrow><mml:mtext> Φ </mml:mtext><mml:mrow><mml:mo> ( </mml:mo><mml:mrow><mml:mi> x </mml:mi><mml:mo> , </mml:mo><mml:mi> t </mml:mi></mml:mrow><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> , bounded by the universal capacity</p>
      <disp-formula id="FD96">
        <label>(9.1)</label>
        <mml:math>
          <mml:mrow>
            <mml:mn>0</mml:mn>
            <mml:mo>≤</mml:mo>
            <mml:mtext>Φ</mml:mtext>
            <mml:mo>≤</mml:mo>
            <mml:msup>
              <mml:mi>c</mml:mi>
              <mml:mn>2</mml:mn>
            </mml:msup>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>All physical phenomena in this framework arise from static or dynamical responses of this bounded field. We now summarize the principal physical implications and organize them into compact mathematical consequences.</p>
      <sec id="sec9dot1">
        <title>9.1. Unified Static and Dynamic Vacuum Response</title>
        <p>Two complementary response regimes follow directly from the behavior of <inline-formula><mml:math><mml:mtext> Φ </mml:mtext></mml:math></inline-formula> :</p>
        <p>Static regime (<inline-formula><mml:math><mml:mrow><mml:msub><mml:mo> ∂ </mml:mo><mml:mi> t </mml:mi></mml:msub><mml:mstyle mathvariant="bold" mathsize="normal"><mml:mi> Φ </mml:mi></mml:mstyle><mml:mo> = </mml:mo><mml:mn> 0 </mml:mn></mml:mrow></mml:math></inline-formula> )</p>
        <p>Spatial relaxation of vacuum-potential deficits produces gravitational interaction. For a localized loading <inline-formula><mml:math><mml:mi> m </mml:mi></mml:math></inline-formula> , the coarse-grained profile derived in Sections III-IV is</p>
        <disp-formula id="FD97">
          <label>(9.2)</label>
          <mml:math>
            <mml:mrow>
              <mml:mtext>Φ</mml:mtext>
              <mml:mrow>
                <mml:mo>(</mml:mo>
                <mml:mi>r</mml:mi>
                <mml:mo>)</mml:mo>
              </mml:mrow>
              <mml:mo>=</mml:mo>
              <mml:msup>
                <mml:mi>c</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mo>−</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:mi>G</mml:mi>
                  <mml:mi>m</mml:mi>
                </mml:mrow>
                <mml:mi>r</mml:mi>
              </mml:mfrac>
              <mml:mo>,</mml:mo>
              <mml:mi>r</mml:mi>
              <mml:mo>≫</mml:mo>
              <mml:msub>
                <mml:mi>r</mml:mi>
                <mml:mi>c</mml:mi>
              </mml:msub>
              <mml:mo>,</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>with collapse radius <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> r </mml:mi><mml:mi> c </mml:mi></mml:msub><mml:mo> = </mml:mo><mml:mrow><mml:mrow><mml:mi> G </mml:mi><mml:mi> m </mml:mi></mml:mrow><mml:mo> / </mml:mo><mml:mrow><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:mrow></mml:mrow></mml:math></inline-formula> . A test loading <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> m </mml:mi><mml:mi> t </mml:mi></mml:msub></mml:mrow></mml:math></inline-formula> experiences acceleration</p>
        <disp-formula id="FD98">
          <label>(9.3)</label>
          <mml:math>
            <mml:mrow>
              <mml:mi>a</mml:mi>
              <mml:mo>=</mml:mo>
              <mml:mo>−</mml:mo>
              <mml:mo>∇</mml:mo>
              <mml:mtext>Φ</mml:mtext>
              <mml:mo>,</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>recovering Newton’s inverse-square law in the weak-field limit [<xref ref-type="bibr" rid="B2">2</xref>][<xref ref-type="bibr" rid="B29">29</xref>].</p>
        <p>Dynamic regime (<inline-formula><mml:math><mml:mrow><mml:msub><mml:mo> ∂ </mml:mo><mml:mi> t </mml:mi></mml:msub><mml:mstyle mathvariant="bold" mathsize="normal"><mml:mi> Φ </mml:mi></mml:mstyle><mml:mo> ≠ </mml:mo><mml:mn> 0 </mml:mn></mml:mrow></mml:math></inline-formula> )</p>
        <p>Small deviations <inline-formula><mml:math><mml:mrow><mml:mi> ϕ </mml:mi><mml:mo> = </mml:mo><mml:mtext> Φ </mml:mtext><mml:mo> − </mml:mo><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:math></inline-formula> satisfy the dynamical equation derived in Section V,</p>
        <disp-formula id="FD99">
          <label>(9.4)</label>
          <mml:math>
            <mml:mrow>
              <mml:msubsup>
                <mml:mo>∂</mml:mo>
                <mml:mi>t</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msubsup>
              <mml:mi>ϕ</mml:mi>
              <mml:mo>=</mml:mo>
              <mml:mfrac>
                <mml:mi>T</mml:mi>
                <mml:mi>μ</mml:mi>
              </mml:mfrac>
              <mml:msup>
                <mml:mo>∇</mml:mo>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mi>ϕ</mml:mi>
              <mml:mo>,</mml:mo>
              <mml:msup>
                <mml:mi>v</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mo>=</mml:mo>
              <mml:mfrac>
                <mml:mi>T</mml:mi>
                <mml:mi>μ</mml:mi>
              </mml:mfrac>
              <mml:mo>≤</mml:mo>
              <mml:msup>
                <mml:mi>c</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mo>,</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>implying the universal propagation bound <inline-formula><mml:math><mml:mrow><mml:mi> v </mml:mi><mml:mo> ≤ </mml:mo><mml:mi> c </mml:mi></mml:mrow></mml:math></inline-formula> .</p>
        <p>Gravitation and wave propagation therefore represent two response modes of the same bounded vacuum field. No independent force law or kinematic postulate is introduced. This unified response structure parallels relational and vacuum-based approaches to gravity [<xref ref-type="bibr" rid="B7">7</xref>][<xref ref-type="bibr" rid="B19">19</xref>].</p>
      </sec>
      <sec id="sec9dot2">
        <title>9.2. Gravitational Redshift and Time Dilation</title>
        <p>Intrinsic oscillation frequencies of physical systems depend on the local vacuum capacity. If <inline-formula><mml:math><mml:mrow><mml:mi> f </mml:mi><mml:mrow><mml:mo> ( </mml:mo><mml:mi> x </mml:mi><mml:mo> ) </mml:mo></mml:mrow><mml:mo> = </mml:mo><mml:mfrac><mml:mrow><mml:mtext> Φ </mml:mtext><mml:mrow><mml:mo> ( </mml:mo><mml:mi> x </mml:mi><mml:mo> ) </mml:mo></mml:mrow></mml:mrow><mml:mrow><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:mfrac></mml:mrow></mml:math></inline-formula> denotes the local capacity fraction, the proper time measured by a local oscillator satisfies</p>
        <disp-formula id="FD100">
          <label>(9.5)</label>
          <mml:math>
            <mml:mrow>
              <mml:mtext>
                 
              </mml:mtext>
              <mml:mtext>d</mml:mtext>
              <mml:mi>τ</mml:mi>
              <mml:mo>=</mml:mo>
              <mml:mi>f</mml:mi>
              <mml:mrow>
                <mml:mo>(</mml:mo>
                <mml:mi>x</mml:mi>
                <mml:mo>)</mml:mo>
              </mml:mrow>
              <mml:mtext>
                 
              </mml:mtext>
              <mml:mtext>d</mml:mtext>
              <mml:mi>t</mml:mi>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>So,</p>
        <disp-formula id="FD101">
          <label>(9.6)</label>
          <mml:math>
            <mml:mrow>
              <mml:mfrac>
                <mml:mrow>
                  <mml:mtext>d</mml:mtext>
                  <mml:mi>τ</mml:mi>
                </mml:mrow>
                <mml:mrow>
                  <mml:mtext>d</mml:mtext>
                  <mml:mi>t</mml:mi>
                </mml:mrow>
              </mml:mfrac>
              <mml:mo>=</mml:mo>
              <mml:mn>1</mml:mn>
              <mml:mo>−</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:mi>G</mml:mi>
                  <mml:mi>M</mml:mi>
                </mml:mrow>
                <mml:mrow>
                  <mml:mi>r</mml:mi>
                  <mml:msup>
                    <mml:mi>c</mml:mi>
                    <mml:mn>2</mml:mn>
                  </mml:msup>
                </mml:mrow>
              </mml:mfrac>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>This relation reproduces the leading weak-field gravitational time-dilation formula obtained in general relativity [<xref ref-type="bibr" rid="B40">40</xref>].</p>
        <p>Within the bounded-vacuum interpretation gravitational redshift arises because local oscillators derive their characteristic energy scale from the surrounding vacuum state. Regions of reduced vacuum capacity therefore exhibit lower intrinsic oscillation frequencies, producing the observed gravitational redshift.</p>
      </sec>
      <sec id="sec9dot3">
        <title>9.3. Light Deflection and Gravitational Lensing</title>
        <p>Spatial gradients of the vacuum-capacity field influence propagation of massless excitations. The emergent metric derived in Section VI yields the standard weak-field line element</p>
        <disp-formula id="FD102">
          <mml:math>
            <mml:mrow>
              <mml:mtext>d</mml:mtext>
              <mml:msup>
                <mml:mi>s</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mo>=</mml:mo>
              <mml:mo>−</mml:mo>
              <mml:mrow>
                <mml:mo>(</mml:mo>
                <mml:mrow>
                  <mml:mn>1</mml:mn>
                  <mml:mo>−</mml:mo>
                  <mml:mfrac>
                    <mml:mrow>
                      <mml:mn>2</mml:mn>
                      <mml:mi>G</mml:mi>
                      <mml:mi>M</mml:mi>
                    </mml:mrow>
                    <mml:mrow>
                      <mml:mi>r</mml:mi>
                      <mml:msup>
                        <mml:mi>c</mml:mi>
                        <mml:mn>2</mml:mn>
                      </mml:msup>
                    </mml:mrow>
                  </mml:mfrac>
                </mml:mrow>
                <mml:mo>)</mml:mo>
              </mml:mrow>
              <mml:msup>
                <mml:mi>c</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mtext>d</mml:mtext>
              <mml:msup>
                <mml:mi>t</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mo>+</mml:mo>
              <mml:mrow>
                <mml:mo>(</mml:mo>
                <mml:mrow>
                  <mml:mn>1</mml:mn>
                  <mml:mo>+</mml:mo>
                  <mml:mfrac>
                    <mml:mrow>
                      <mml:mn>2</mml:mn>
                      <mml:mi>G</mml:mi>
                      <mml:mi>M</mml:mi>
                    </mml:mrow>
                    <mml:mrow>
                      <mml:mi>r</mml:mi>
                      <mml:msup>
                        <mml:mi>c</mml:mi>
                        <mml:mn>2</mml:mn>
                      </mml:msup>
                    </mml:mrow>
                  </mml:mfrac>
                </mml:mrow>
                <mml:mo>)</mml:mo>
              </mml:mrow>
              <mml:mtext>d</mml:mtext>
              <mml:msup>
                <mml:mi>l</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>Propagation of light in this metric produces the well-known relativistic deflection angle</p>
        <disp-formula id="FD103">
          <label>(9.7)</label>
          <mml:math>
            <mml:mrow>
              <mml:mi>θ</mml:mi>
              <mml:mo>=</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:mn>4</mml:mn>
                  <mml:mi>G</mml:mi>
                  <mml:mi>M</mml:mi>
                </mml:mrow>
                <mml:mrow>
                  <mml:mi>b</mml:mi>
                  <mml:msup>
                    <mml:mi>c</mml:mi>
                    <mml:mn>2</mml:mn>
                  </mml:msup>
                </mml:mrow>
              </mml:mfrac>
              <mml:mo>,</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>for a ray passing a mass <inline-formula><mml:math><mml:mi> M </mml:mi></mml:math></inline-formula> with impact parameter <inline-formula><mml:math><mml:mrow><mml:mi> b </mml:mi><mml:mo></mml:mo></mml:mrow></mml:math></inline-formula> [<xref ref-type="bibr" rid="B2">2</xref>][<xref ref-type="bibr" rid="B18">18</xref>].</p>
        <p>In the bounded-vacuum interpretation gravitational lensing arises because gradients of vacuum capacity modify both the local clock rate and spatial measurement scale governing wave propagation. The effect can therefore be interpreted as refraction of vacuum-supported modes in an inhomogeneous medium whose optical properties depend on the local vacuum state, paralleling optical-metric and analogue-gravity descriptions [<xref ref-type="bibr" rid="B23">23</xref>][<xref ref-type="bibr" rid="B41">41</xref>].</p>
      </sec>
      <sec id="sec9dot4">
        <title>9.4. Horizons and Vacuum Saturation</title>
        <p>Finite vacuum capacity implies a natural limit to gravitational localization. The loading bound derived earlier can be expressed as</p>
        <disp-formula id="FD104">
          <label>(9.8)</label>
          <mml:math>
            <mml:mrow>
              <mml:mfrac>
                <mml:mi>m</mml:mi>
                <mml:mi>r</mml:mi>
              </mml:mfrac>
              <mml:mo>≲</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:msup>
                    <mml:mi>c</mml:mi>
                    <mml:mn>2</mml:mn>
                  </mml:msup>
                </mml:mrow>
                <mml:mi>G</mml:mi>
              </mml:mfrac>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>Saturation of this condition defines the characteristic vacuum-loading scale</p>
        <disp-formula id="FD105">
          <label>(9.9)</label>
          <mml:math>
            <mml:mrow>
              <mml:msub>
                <mml:mi>r</mml:mi>
                <mml:mi>c</mml:mi>
              </mml:msub>
              <mml:mo>=</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:mi>G</mml:mi>
                  <mml:mi>m</mml:mi>
                </mml:mrow>
                <mml:mrow>
                  <mml:msup>
                    <mml:mi>c</mml:mi>
                    <mml:mn>2</mml:mn>
                  </mml:msup>
                </mml:mrow>
              </mml:mfrac>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>In the emergent metric description developed in Section VI, the physical horizon radius corresponds to</p>
        <disp-formula id="FD106">
          <label>(9.10)</label>
          <mml:math>
            <mml:mrow>
              <mml:msub>
                <mml:mi>r</mml:mi>
                <mml:mi>h</mml:mi>
              </mml:msub>
              <mml:mo>=</mml:mo>
              <mml:mn>2</mml:mn>
              <mml:msub>
                <mml:mi>r</mml:mi>
                <mml:mi>c</mml:mi>
              </mml:msub>
              <mml:mo>=</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:mn>2</mml:mn>
                  <mml:mi>G</mml:mi>
                  <mml:mi>M</mml:mi>
                </mml:mrow>
                <mml:mrow>
                  <mml:msup>
                    <mml:mi>c</mml:mi>
                    <mml:mn>2</mml:mn>
                  </mml:msup>
                </mml:mrow>
              </mml:mfrac>
              <mml:mo>,</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>which coincides with the Schwarzschild horizon obtained in general relativity [<xref ref-type="bibr" rid="B2">2</xref>][<xref ref-type="bibr" rid="B18">18</xref>].</p>
        <p>Within the bounded-vacuum framework horizon formation therefore corresponds to the onset of vacuum-capacity saturation in which the available vacuum potential approaches its limiting value. The horizon marks the boundary beyond which further concentration of vacuum loading cannot be supported within the classical continuum description.</p>
        <p>Because localization cannot proceed below the Planck scale</p>
        <disp-formula id="FD107">
          <label>(9.11)</label>
          <mml:math>
            <mml:mrow>
              <mml:msub>
                <mml:mi>ℓ</mml:mi>
                <mml:mi>P</mml:mi>
              </mml:msub>
              <mml:mo>=</mml:mo>
              <mml:msqrt>
                <mml:mrow>
                  <mml:mfrac>
                    <mml:mrow>
                      <mml:mi>ℏ</mml:mi>
                      <mml:mi>G</mml:mi>
                    </mml:mrow>
                    <mml:mrow>
                      <mml:msup>
                        <mml:mi>c</mml:mi>
                        <mml:mn>3</mml:mn>
                      </mml:msup>
                    </mml:mrow>
                  </mml:mfrac>
                </mml:mrow>
              </mml:msqrt>
              <mml:mo>,</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>the vacuum response remains finite even in extreme gravitational configurations. Classical singularities are therefore replaced by finite saturation regions, consistent with regular black-hole models and quantum-gravity motivated singularity-resolution scenarios [<xref ref-type="bibr" rid="B42">42</xref>][<xref ref-type="bibr" rid="B43">43</xref>].</p>
      </sec>
      <sec id="sec9dot5">
        <title>9.5. Vacuum Correlation and Entanglement</title>
        <p>The vacuum field <inline-formula><mml:math><mml:mrow><mml:mtext> Φ </mml:mtext><mml:mrow><mml:mo> ( </mml:mo><mml:mrow><mml:mi> x </mml:mi><mml:mo> , </mml:mo><mml:mi> t </mml:mi></mml:mrow><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> is globally defined and supports propagating oscillatory modes. Localized loadings therefore modify the surrounding vacuum configuration and naturally generate correlations between spatially separated regions.</p>
        <p>Within this interpretation quantum entanglement may be viewed as arising from correlated excitations of the underlying vacuum medium established during joint formation processes. Such correlations do not require superluminal information transfer, since dynamical propagation of disturbances remains bounded by <inline-formula><mml:math><mml:mrow><mml:mi> v </mml:mi><mml:mo> ≤ </mml:mo><mml:mi> c </mml:mi></mml:mrow></mml:math></inline-formula> .</p>
        <p>The bounded-vacuum framework therefore provides a medium-based interpretation of quantum correlations while remaining compatible with standard quantum theory [<xref ref-type="bibr" rid="B7">7</xref>].</p>
      </sec>
      <sec id="sec9dot6">
        <title>9.6. Unified Capacity Bounds</title>
        <p>All derived phenomena reduce to manifestations of finite vacuum transmissibility. The universal bounds are</p>
        <disp-formula id="FD108">
          <label>(9.12)</label>
          <mml:math>
            <mml:mrow>
              <mml:mtext>Φ</mml:mtext>
              <mml:mo>≤</mml:mo>
              <mml:msup>
                <mml:mi>c</mml:mi>
                <mml:mn>2</mml:mn>
              </mml:msup>
              <mml:mo>,</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <disp-formula id="FD109">
          <label>(9.13)</label>
          <mml:math>
            <mml:mrow>
              <mml:mfrac>
                <mml:mi>m</mml:mi>
                <mml:mi>L</mml:mi>
              </mml:mfrac>
              <mml:mo>≤</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:msup>
                    <mml:mi>c</mml:mi>
                    <mml:mn>2</mml:mn>
                  </mml:msup>
                </mml:mrow>
                <mml:mi>G</mml:mi>
              </mml:mfrac>
              <mml:mo>,</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <disp-formula id="FD110">
          <label>(9.14)</label>
          <mml:math>
            <mml:mrow>
              <mml:mi>F</mml:mi>
              <mml:mo>≤</mml:mo>
              <mml:msub>
                <mml:mi>F</mml:mi>
                <mml:mrow>
                  <mml:mtext>max</mml:mtext>
                </mml:mrow>
              </mml:msub>
              <mml:mo>=</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:msup>
                    <mml:mi>c</mml:mi>
                    <mml:mn>4</mml:mn>
                  </mml:msup>
                </mml:mrow>
                <mml:mi>G</mml:mi>
              </mml:mfrac>
              <mml:mo>,</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <disp-formula id="FD111">
          <label>(9.15)</label>
          <mml:math>
            <mml:mrow>
              <mml:mi>v</mml:mi>
              <mml:mo>≤</mml:mo>
              <mml:mi>c</mml:mi>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>Gravitational interaction, inertia, maximum force, invariant signal speed, horizon formation, and Planck-scale saturation are therefore not independent principles. They arise as different manifestations of a single structural property: finite vacuum-potential capacity.</p>
      </sec>
      <sec id="sec9dot7">
        <title>9.7. Hierarchy and Planck-Scale Suppression of Gravitation</title>
        <p>A central puzzle in fundamental physics is the extreme weakness of gravitation compared with gauge interactions. For example, the ratio of gravitational to electromagnetic forces between elementary particles is of order <inline-formula><mml:math><mml:mrow><mml:msup><mml:mrow><mml:mn> 10 </mml:mn></mml:mrow><mml:mrow><mml:mo> − </mml:mo><mml:mn> 39 </mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math></inline-formula> [<xref ref-type="bibr" rid="B44">44</xref>]. In conventional theory, this disparity is encoded in Newton’s constant <inline-formula><mml:math><mml:mi> G </mml:mi></mml:math></inline-formula> [<xref ref-type="bibr" rid="B11">11</xref>][<xref ref-type="bibr" rid="B24">24</xref>], while the associated natural mass scale is the Planck mass <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> m </mml:mi><mml:mi> P </mml:mi></mml:msub><mml:mo> = </mml:mo><mml:msqrt><mml:mrow><mml:mrow><mml:mrow><mml:mi> ℏ </mml:mi><mml:mi> c </mml:mi></mml:mrow><mml:mo> / </mml:mo><mml:mi> G </mml:mi></mml:mrow></mml:mrow></mml:msqrt></mml:mrow></mml:math></inline-formula> .</p>
        <p>Within the bounded-vacuum framework, the weakness of gravity follows from finite vacuum capacity and stiffness. A localized mass <inline-formula><mml:math><mml:mi> m </mml:mi></mml:math></inline-formula> induces the static relaxation profile</p>
        <disp-formula id="FD112">
          <label>(9.16)</label>
          <mml:math>
            <mml:mrow>
              <mml:mi>δ</mml:mi>
              <mml:mtext>Φ</mml:mtext>
              <mml:mrow>
                <mml:mo>(</mml:mo>
                <mml:mi>r</mml:mi>
                <mml:mo>)</mml:mo>
              </mml:mrow>
              <mml:mo>=</mml:mo>
              <mml:mo>−</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:mi>G</mml:mi>
                  <mml:mi>m</mml:mi>
                </mml:mrow>
                <mml:mi>r</mml:mi>
              </mml:mfrac>
              <mml:mo>,</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>consistent with the Newtonian limit of relativistic gravity [<xref ref-type="bibr" rid="B11">11</xref>][<xref ref-type="bibr" rid="B24">24</xref>]. The physically relevant quantity is the fractional deformation of the bounded vacuum potential <inline-formula><mml:math><mml:mrow><mml:msub><mml:mtext> Φ </mml:mtext><mml:mn> 0 </mml:mn></mml:msub><mml:mo> = </mml:mo><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:math></inline-formula> ,</p>
        <disp-formula id="FD113">
          <label>(9.17)</label>
          <mml:math>
            <mml:mrow>
              <mml:mfrac>
                <mml:mrow>
                  <mml:mrow>
                    <mml:mo>|</mml:mo>
                    <mml:mrow>
                      <mml:mi>δ</mml:mi>
                      <mml:mtext>Φ</mml:mtext>
                    </mml:mrow>
                    <mml:mo>|</mml:mo>
                  </mml:mrow>
                </mml:mrow>
                <mml:mrow>
                  <mml:msup>
                    <mml:mi>c</mml:mi>
                    <mml:mn>2</mml:mn>
                  </mml:msup>
                </mml:mrow>
              </mml:mfrac>
              <mml:mo>=</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:mi>G</mml:mi>
                  <mml:mi>m</mml:mi>
                </mml:mrow>
                <mml:mrow>
                  <mml:mi>r</mml:mi>
                  <mml:msup>
                    <mml:mi>c</mml:mi>
                    <mml:mn>2</mml:mn>
                  </mml:msup>
                </mml:mrow>
              </mml:mfrac>
              <mml:mo>=</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:msub>
                    <mml:mi>r</mml:mi>
                    <mml:mi>c</mml:mi>
                  </mml:msub>
                </mml:mrow>
                <mml:mi>r</mml:mi>
              </mml:mfrac>
              <mml:mo>,</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>where the collapse radius is</p>
        <disp-formula id="FD114">
          <label>(9.18)</label>
          <mml:math>
            <mml:mrow>
              <mml:msub>
                <mml:mi>r</mml:mi>
                <mml:mi>c</mml:mi>
              </mml:msub>
              <mml:mo>=</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:mi>G</mml:mi>
                  <mml:mi>m</mml:mi>
                </mml:mrow>
                <mml:mrow>
                  <mml:msup>
                    <mml:mi>c</mml:mi>
                    <mml:mn>2</mml:mn>
                  </mml:msup>
                </mml:mrow>
              </mml:mfrac>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>For ordinary systems, <inline-formula><mml:math><mml:mrow><mml:mi> r </mml:mi><mml:mo> ≫ </mml:mo><mml:msub><mml:mi> r </mml:mi><mml:mi> c </mml:mi></mml:msub></mml:mrow></mml:math></inline-formula> , so gravitation corresponds to a minute fractional redistribution of a vacuum potential whose natural scale is <inline-formula><mml:math><mml:mrow><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:math></inline-formula> . This suppression reflects the extreme stiffness of the vacuum network, whose maximal transmissible tension is</p>
        <disp-formula id="FD115">
          <label>(9.19)</label>
          <mml:math>
            <mml:mrow>
              <mml:msub>
                <mml:mi>F</mml:mi>
                <mml:mrow>
                  <mml:mtext>max</mml:mtext>
                </mml:mrow>
              </mml:msub>
              <mml:mo>=</mml:mo>
              <mml:mfrac>
                <mml:mrow>
                  <mml:msup>
                    <mml:mi>c</mml:mi>
                    <mml:mn>4</mml:mn>
                  </mml:msup>
                </mml:mrow>
                <mml:mi>G</mml:mi>
              </mml:mfrac>
              <mml:mo>,</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>a quantity related to relativistic upper force bounds [<xref ref-type="bibr" rid="B4">4</xref>].</p>
        <p>Expressing the collapse scale in terms of the Planck mass,</p>
        <disp-formula id="FD116">
          <label>(9.20)</label>
          <mml:math>
            <mml:mrow>
              <mml:msub>
                <mml:mi>m</mml:mi>
                <mml:mi>P</mml:mi>
              </mml:msub>
              <mml:mo>=</mml:mo>
              <mml:msqrt>
                <mml:mrow>
                  <mml:mfrac>
                    <mml:mrow>
                      <mml:mi>ℏ</mml:mi>
                      <mml:mi>c</mml:mi>
                    </mml:mrow>
                    <mml:mi>G</mml:mi>
                  </mml:mfrac>
                </mml:mrow>
              </mml:msqrt>
              <mml:mo>,</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>the dimensionless gravitational strength of a localized excitation becomes</p>
        <disp-formula id="FD117">
          <label>(9.21)</label>
          <mml:math>
            <mml:mrow>
              <mml:mfrac>
                <mml:mi>m</mml:mi>
                <mml:mrow>
                  <mml:msub>
                    <mml:mi>m</mml:mi>
                    <mml:mi>P</mml:mi>
                  </mml:msub>
                </mml:mrow>
              </mml:mfrac>
              <mml:mo>.</mml:mo>
            </mml:mrow>
          </mml:math>
        </disp-formula>
        <p>Since all known elementary masses satisfy <inline-formula><mml:math><mml:mrow><mml:mi> m </mml:mi><mml:mo> ≪ </mml:mo><mml:msub><mml:mi> m </mml:mi><mml:mi> P </mml:mi></mml:msub></mml:mrow></mml:math></inline-formula> , gravitational effects are parametrically suppressed by the Planck scale.</p>
        <p>The apparent smallness of <inline-formula><mml:math><mml:mi> G </mml:mi></mml:math></inline-formula> is therefore reinterpreted as a consequence of Planck-scale vacuum stiffness: gravity measures the global fractional loading of a bounded medium, becoming non-perturbative only when <inline-formula><mml:math><mml:mrow><mml:mi> m </mml:mi><mml:mo> ∼ </mml:mo><mml:msub><mml:mi> m </mml:mi><mml:mi> P </mml:mi></mml:msub></mml:mrow></mml:math></inline-formula> or equivalently <inline-formula><mml:math><mml:mrow><mml:mi> r </mml:mi><mml:mo> ∼ </mml:mo><mml:msub><mml:mi> r </mml:mi><mml:mi> c </mml:mi></mml:msub></mml:mrow></mml:math></inline-formula> .</p>
      </sec>
    </sec>
    <sec id="sec10">
      <title>10. Section X—Conclusions and Outlook</title>
      <p>We have developed a bounded-vacuum framework in which gravitational phenomena arise from the redistribution of a scalar vacuum-potential field <inline-formula><mml:math><mml:mrow><mml:mtext> Φ </mml:mtext><mml:mrow><mml:mo> ( </mml:mo><mml:mrow><mml:mi> x </mml:mi><mml:mo> , </mml:mo><mml:mi> t </mml:mi></mml:mrow><mml:mo> ) </mml:mo></mml:mrow></mml:mrow></mml:math></inline-formula> whose magnitude is limited by the universal capacity</p>
      <disp-formula id="FD118">
        <mml:math>
          <mml:mrow>
            <mml:mn>0</mml:mn>
            <mml:mo>≤</mml:mo>
            <mml:mtext>Φ</mml:mtext>
            <mml:mo>≤</mml:mo>
            <mml:msup>
              <mml:mi>c</mml:mi>
              <mml:mn>2</mml:mn>
            </mml:msup>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>Within this description the vacuum behaves as a physical medium with finite transmissibility. Static gravitational configurations and dynamical excitations represent complementary response modes of the same bounded field.</p>
      <p>In the static regime, spatial relaxation of vacuum-capacity deficits generated by localized loading produces the potential profile</p>
      <disp-formula id="FD119">
        <mml:math>
          <mml:mrow>
            <mml:mtext>Φ</mml:mtext>
            <mml:mrow>
              <mml:mo>(</mml:mo>
              <mml:mi>r</mml:mi>
              <mml:mo>)</mml:mo>
            </mml:mrow>
            <mml:mo>=</mml:mo>
            <mml:msup>
              <mml:mi>c</mml:mi>
              <mml:mn>2</mml:mn>
            </mml:msup>
            <mml:mo>−</mml:mo>
            <mml:mfrac>
              <mml:mrow>
                <mml:mi>G</mml:mi>
                <mml:mi>m</mml:mi>
              </mml:mrow>
              <mml:mi>r</mml:mi>
            </mml:mfrac>
            <mml:mo>,</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>which reproduces Newtonian gravity in the weak-field limit. In the dynamical regime, perturbations of the vacuum field propagate according to the wave equation derived earlier, with propagation velocity determined by the stiffness-to-inertia ratio of the vacuum response. The bounded-capacity condition naturally yields the universal signal-speed bound <inline-formula><mml:math><mml:mrow><mml:mi> v </mml:mi><mml:mo> ≤ </mml:mo><mml:mi> c </mml:mi></mml:mrow></mml:math></inline-formula> and the maximum transmissible force</p>
      <disp-formula id="FD120">
        <mml:math>
          <mml:mrow>
            <mml:msub>
              <mml:mi>F</mml:mi>
              <mml:mrow>
                <mml:mtext>max</mml:mtext>
              </mml:mrow>
            </mml:msub>
            <mml:mo>=</mml:mo>
            <mml:mfrac>
              <mml:mrow>
                <mml:msup>
                  <mml:mi>c</mml:mi>
                  <mml:mn>4</mml:mn>
                </mml:msup>
              </mml:mrow>
              <mml:mi>G</mml:mi>
            </mml:mfrac>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>A key result of the framework is that variations of the vacuum potential modify both clock rates and spatial measurement standards. These effects generate an effective spacetime metric whose weak-field limit reproduces the standard relativistic metric. In this sense spacetime geometry emerges as a macroscopic description of variations in the vacuum potential.</p>
      <p>Combining quantum action quantization <inline-formula><mml:math><mml:mrow><mml:mtext> Δ </mml:mtext><mml:mi> S </mml:mi><mml:mo> ∼ </mml:mo><mml:mi> ℏ </mml:mi></mml:mrow></mml:math></inline-formula> with the gravitational localization constraint <inline-formula><mml:math><mml:mrow><mml:msub><mml:mi> r </mml:mi><mml:mi> c </mml:mi></mml:msub><mml:mo> ∼ </mml:mo><mml:mrow><mml:mrow><mml:mi> G </mml:mi><mml:mi> m </mml:mi></mml:mrow><mml:mo> / </mml:mo><mml:mrow><mml:msup><mml:mi> c </mml:mi><mml:mn> 2 </mml:mn></mml:msup></mml:mrow></mml:mrow></mml:mrow></mml:math></inline-formula> yields a unique saturation scale characterized by the Planck mass</p>
      <disp-formula id="FD121">
        <mml:math>
          <mml:mrow>
            <mml:msub>
              <mml:mi>m</mml:mi>
              <mml:mi>P</mml:mi>
            </mml:msub>
            <mml:mo>=</mml:mo>
            <mml:msqrt>
              <mml:mrow>
                <mml:mfrac>
                  <mml:mrow>
                    <mml:mi>ℏ</mml:mi>
                    <mml:mi>c</mml:mi>
                  </mml:mrow>
                  <mml:mi>G</mml:mi>
                </mml:mfrac>
              </mml:mrow>
            </mml:msqrt>
            <mml:mo>,</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>and the Planck length</p>
      <disp-formula id="FD122">
        <mml:math>
          <mml:mrow>
            <mml:msub>
              <mml:mi>ℓ</mml:mi>
              <mml:mi>P</mml:mi>
            </mml:msub>
            <mml:mo>=</mml:mo>
            <mml:msqrt>
              <mml:mrow>
                <mml:mfrac>
                  <mml:mrow>
                    <mml:mi>ℏ</mml:mi>
                    <mml:mi>G</mml:mi>
                  </mml:mrow>
                  <mml:mrow>
                    <mml:msup>
                      <mml:mi>c</mml:mi>
                      <mml:mn>3</mml:mn>
                    </mml:msup>
                  </mml:mrow>
                </mml:mfrac>
              </mml:mrow>
            </mml:msqrt>
            <mml:mo>.</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>These scales arise not as fundamental inputs but as intersection points of independent vacuum-capacity constraints. The Planck scale therefore represents the minimal response scale of the vacuum medium.</p>
      <p>At microscopic scales the existence of this minimal response length suggests a lattice-like realization of the vacuum field. Such a structure produces relativistic dispersion in the infrared limit together with Planck-suppressed corrections at high energies. The resulting quadratic modification of the propagation velocity,</p>
      <disp-formula id="FD123">
        <mml:math>
          <mml:mrow>
            <mml:mfrac>
              <mml:mrow>
                <mml:mtext>Δ</mml:mtext>
                <mml:mi>v</mml:mi>
              </mml:mrow>
              <mml:mi>c</mml:mi>
            </mml:mfrac>
            <mml:mo>∼</mml:mo>
            <mml:mo>−</mml:mo>
            <mml:mfrac>
              <mml:mn>1</mml:mn>
              <mml:mn>8</mml:mn>
            </mml:mfrac>
            <mml:msup>
              <mml:mrow>
                <mml:mrow>
                  <mml:mo>(</mml:mo>
                  <mml:mrow>
                    <mml:mfrac>
                      <mml:mi>E</mml:mi>
                      <mml:mrow>
                        <mml:msub>
                          <mml:mi>E</mml:mi>
                          <mml:mi>P</mml:mi>
                        </mml:msub>
                      </mml:mrow>
                    </mml:mfrac>
                  </mml:mrow>
                  <mml:mo>)</mml:mo>
                </mml:mrow>
              </mml:mrow>
              <mml:mn>2</mml:mn>
            </mml:msup>
            <mml:mo>,</mml:mo>
          </mml:mrow>
        </mml:math>
      </disp-formula>
      <p>is consistent with existing observational bounds on Lorentz-violating dispersion.</p>
      <p>Configurations approaching the gravitational loading bound correspond to regimes of vacuum saturation. In the emergent metric description these regimes produce horizon formation, while the bounded nature of the vacuum response prevents divergent field amplitudes. Classical singularities are therefore replaced by finite saturation regions within the effective continuum description.</p>
      <p>Several directions remain open for further investigation. These include developing a fully covariant dynamical formulation of the vacuum-capacity field, analyzing nonlinear and strong-loading regimes beyond the weak-field approximation, and investigating possible couplings between the vacuum potential and standard matter fields. Cosmological evolution of the vacuum capacity and potential observational signatures of Planck-suppressed dispersion also remain important topics for future work.</p>
      <p>The bounded-vacuum framework thus provides a unified medium-based perspective in which the constants <inline-formula><mml:math><mml:mi> c </mml:mi></mml:math></inline-formula> , <inline-formula><mml:math><mml:mi> G </mml:mi></mml:math></inline-formula> , and <inline-formula><mml:math><mml:mi> ℏ </mml:mi></mml:math></inline-formula> appear as structural parameters governing the transmissibility and response of the vacuum. Whether this description can be extended into a fully predictive ultraviolet-complete theory remains an open question, but the results presented here suggest that many features of gravitational physics may emerge from the finite capacity of the physical vacuum.</p>
    </sec>
    <sec id="sec11">
      <title>Acknowledgements</title>
      <p>The authors sincerely acknowledge Dr. D. Kanjilal (IUAC), Dr. Jyoti Malik (Government College, Rewari), and Dr. Vinamrita Singh (NSUT, Delhi) for their valuable discussions, insightful suggestions, and continuous support throughout the course of this work.</p>
    </sec>
  </body>
  <back>
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