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		<title>JonoThora: Psionics expansion (01a + 01b): content authored / LaTeX-restored per local submodule; lint-clean.</title>
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		<summary type="html">&lt;p&gt;Psionics expansion (01a + 01b): content authored / LaTeX-restored per local submodule; lint-clean.&lt;/p&gt;
&lt;p&gt;&lt;b&gt;New page&lt;/b&gt;&lt;/p&gt;&lt;div&gt;= 5D Action Principle =&lt;br /&gt;
&lt;br /&gt;
{{Audience_Sidebar&lt;br /&gt;
| difficulty   = Advanced&lt;br /&gt;
| reading_time = 25 minutes&lt;br /&gt;
| prerequisites = [[Psionics_Primer]]; calculus of variations; tensor index notation; basic GR (Einstein–Hilbert action); basic [[Kaluza-Klein_Unification|Kaluza–Klein]]; familiarity with [[Symbol_Glossary]].&lt;br /&gt;
| if_too_advanced_see = [[Why_Does_Physics_Need_Extra_Dimensions]]&lt;br /&gt;
}}&lt;br /&gt;
&lt;br /&gt;
{{Notation&lt;br /&gt;
| psi_convention   = ψ = scalar field amplitude; Ψ = T&amp;lt;sup&amp;gt;00&amp;lt;/sup&amp;gt;(ψ) energy density (defined on [[Psi_Field]]).&lt;br /&gt;
| signature        = Mostly-plus (−,+,+,+) in 4D; extended to (−,+,+,+,+) in 5D.&lt;br /&gt;
| units            = ℏ = c = 1 unless explicitly noted.&lt;br /&gt;
| index_convention = Capital M,N,P,… run 0–4 (all 5D); Greek μ,ν,ρ,σ run 0–3 (4D); Latin i,j,k run 1–3 (spatial). The compact fifth coordinate is x&amp;lt;sup&amp;gt;5&amp;lt;/sup&amp;gt;.&lt;br /&gt;
}}&lt;br /&gt;
&lt;br /&gt;
The &amp;#039;&amp;#039;&amp;#039;5D Action Principle&amp;#039;&amp;#039;&amp;#039; is the deepest layer of the psionic theoretical framework. From a single 5D action it derives, by compactification and variation, the entire equation set on [[Psionics]]: the master ψ field equation, the modified Einstein equations, the gravitomagnetic coupling, and (in the appropriate limit) the Yukawa form of [[Psi_Field|ψ-screening]].&lt;br /&gt;
&lt;br /&gt;
This page presents the derivation in full, with every symbol defined and every step of the reduction shown. For symbol-only reference, see [[Symbol_Glossary]]. For a tour of which-known-physics-it-reduces-to, see [[Sanity_Check_Limits]].&lt;br /&gt;
&lt;br /&gt;
== The Action ==&lt;br /&gt;
&lt;br /&gt;
The total action of the 5D scalar-tensor theory underlying psionics is:&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math display=&amp;quot;block&amp;quot;&amp;gt;S = \int d^5x \, \sqrt{-\tilde{g}} \left[ \frac{\tilde{R}}{16\pi \tilde{G}} - \tfrac{1}{2} \tilde{g}^{MN} \partial_M \psi \, \partial_N \psi - \tfrac{1}{2} m^2 \psi^2 - \frac{\lambda}{4} \psi^4 - \tfrac{1}{4} e^{k\psi} \tilde{F}_{MN} \tilde{F}^{MN} + J_\psi \psi \right]&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
This single expression generates everything on [[Psionics]] by:&lt;br /&gt;
&lt;br /&gt;
* Compactifying the fifth dimension → 4D effective theory.&lt;br /&gt;
* Taking the non-relativistic limit → Yukawa / Poisson form.&lt;br /&gt;
* Varying with respect to ψ → field equation.&lt;br /&gt;
* Varying with respect to g̃&amp;lt;sub&amp;gt;MN&amp;lt;/sub&amp;gt; → modified Einstein equations.&lt;br /&gt;
&lt;br /&gt;
== Symbol glossary ==&lt;br /&gt;
&lt;br /&gt;
=== Indices and coordinates ===&lt;br /&gt;
&lt;br /&gt;
{| class=&amp;quot;wikitable&amp;quot;&lt;br /&gt;
! Symbol !! Range !! Meaning&lt;br /&gt;
|-&lt;br /&gt;
| M, N, P, … || 0–4 || All 5 spacetime dimensions (1 time + 3 ordinary spatial + 1 compact)&lt;br /&gt;
|-&lt;br /&gt;
| μ, ν, ρ, σ || 0–3 || Ordinary 4D spacetime&lt;br /&gt;
|-&lt;br /&gt;
| i, j, k || 1–3 || Spatial only&lt;br /&gt;
|-&lt;br /&gt;
| x&amp;lt;sup&amp;gt;M&amp;lt;/sup&amp;gt; || — || A point in 5D spacetime, x&amp;lt;sup&amp;gt;M&amp;lt;/sup&amp;gt; = (x&amp;lt;sup&amp;gt;0&amp;lt;/sup&amp;gt;, x&amp;lt;sup&amp;gt;1&amp;lt;/sup&amp;gt;, x&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt;, x&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;, x&amp;lt;sup&amp;gt;5&amp;lt;/sup&amp;gt;)&lt;br /&gt;
|-&lt;br /&gt;
| x&amp;lt;sup&amp;gt;5&amp;lt;/sup&amp;gt; || period 2πL || Compact fifth coordinate; L is the [[Compactification_in_Kaluza-Klein|compactification radius]]&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
=== Metric and curvature ===&lt;br /&gt;
&lt;br /&gt;
{| class=&amp;quot;wikitable&amp;quot;&lt;br /&gt;
! Symbol !! Units !! Meaning&lt;br /&gt;
|-&lt;br /&gt;
| g̃&amp;lt;sub&amp;gt;MN&amp;lt;/sub&amp;gt; || dimensionless || 5D metric tensor (symmetric, 15 independent components)&lt;br /&gt;
|-&lt;br /&gt;
| g&amp;lt;sub&amp;gt;μν&amp;lt;/sub&amp;gt; || dimensionless || 4D metric tensor (the GR metric)&lt;br /&gt;
|-&lt;br /&gt;
| ϕ || dimensionless || [[Dilaton]]; encodes the local size of the compact dimension&lt;br /&gt;
|-&lt;br /&gt;
| A&amp;lt;sub&amp;gt;μ&amp;lt;/sub&amp;gt; || V·s/m || EM 4-potential; emerges from g̃&amp;lt;sub&amp;gt;μ5&amp;lt;/sub&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
| g̃ || dimensionless || Determinant of g̃&amp;lt;sub&amp;gt;MN&amp;lt;/sub&amp;gt;; appears in √(−g̃) volume element&lt;br /&gt;
|-&lt;br /&gt;
| R̃ || 1/length&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt; || 5D Ricci scalar (total curvature)&lt;br /&gt;
|-&lt;br /&gt;
| R̃&amp;lt;sub&amp;gt;MN&amp;lt;/sub&amp;gt; || 1/length&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt; || 5D Ricci tensor&lt;br /&gt;
|-&lt;br /&gt;
| G̃ || m&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;/(kg·s&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt;) || 5D Newton constant&lt;br /&gt;
|-&lt;br /&gt;
| G || 6.674 × 10&amp;lt;sup&amp;gt;−11&amp;lt;/sup&amp;gt; m&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;/(kg·s&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt;) || 4D Newton constant after KK reduction&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
=== The psionic scalar field ===&lt;br /&gt;
&lt;br /&gt;
{| class=&amp;quot;wikitable&amp;quot;&lt;br /&gt;
! Symbol !! Units (SI) !! Meaning&lt;br /&gt;
|-&lt;br /&gt;
| ψ || √(J/m&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;) · m || Psionic scalar amplitude&lt;br /&gt;
|-&lt;br /&gt;
| ∂&amp;lt;sub&amp;gt;M&amp;lt;/sub&amp;gt;ψ || √(J/m) / m || 5-gradient&lt;br /&gt;
|-&lt;br /&gt;
| □ψ || √(J/m) / m&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt; || d&amp;#039;Alembertian (□ = g&amp;lt;sup&amp;gt;μν&amp;lt;/sup&amp;gt;∂&amp;lt;sub&amp;gt;μ&amp;lt;/sub&amp;gt;∂&amp;lt;sub&amp;gt;ν&amp;lt;/sub&amp;gt;)&lt;br /&gt;
|-&lt;br /&gt;
| m || 1/length || ψ-field mass; Yukawa range is 1/m&lt;br /&gt;
|-&lt;br /&gt;
| λ || dimensionless || Quartic self-coupling; λ &amp;gt; 0 stabilises the field and supports [[Soliton_Solutions_of_Psi_Field|solitons]]&lt;br /&gt;
|-&lt;br /&gt;
| J&amp;lt;sub&amp;gt;ψ&amp;lt;/sub&amp;gt; || √(J/m) / m&amp;lt;sup&amp;gt;4&amp;lt;/sup&amp;gt; || External source — coherent neural firing, focused attention, technological emitter&lt;br /&gt;
|-&lt;br /&gt;
| ρ&amp;lt;sub&amp;gt;ψ&amp;lt;/sub&amp;gt; || √(J·m) / m&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt; || Non-relativistic limit of J&amp;lt;sub&amp;gt;ψ&amp;lt;/sub&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
| p || √(J·m) || Psionic charge of a test particle&lt;br /&gt;
|-&lt;br /&gt;
| G&amp;lt;sub&amp;gt;ψ&amp;lt;/sub&amp;gt; || m&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt;/(kg·s&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt;) || Psionic coupling constant&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
=== Electromagnetic and interaction ===&lt;br /&gt;
&lt;br /&gt;
{| class=&amp;quot;wikitable&amp;quot;&lt;br /&gt;
! Symbol !! Meaning&lt;br /&gt;
|-&lt;br /&gt;
| F̃&amp;lt;sub&amp;gt;MN&amp;lt;/sub&amp;gt; || 5D EM field-strength tensor; F̃&amp;lt;sub&amp;gt;MN&amp;lt;/sub&amp;gt; = ∂&amp;lt;sub&amp;gt;M&amp;lt;/sub&amp;gt;Ã&amp;lt;sub&amp;gt;N&amp;lt;/sub&amp;gt; − ∂&amp;lt;sub&amp;gt;N&amp;lt;/sub&amp;gt;Ã&amp;lt;sub&amp;gt;M&amp;lt;/sub&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
| F&amp;lt;sub&amp;gt;μν&amp;lt;/sub&amp;gt; || 4D EM field-strength tensor&lt;br /&gt;
|-&lt;br /&gt;
| F&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt; ≡ F&amp;lt;sub&amp;gt;μν&amp;lt;/sub&amp;gt;F&amp;lt;sup&amp;gt;μν&amp;lt;/sup&amp;gt; || Lorentz invariant: proportional to B&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt;c&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt; − E&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
| α || ψ–EM coupling (4D effective)&lt;br /&gt;
|-&lt;br /&gt;
| κ || ψ–EM scale (5D)&lt;br /&gt;
|-&lt;br /&gt;
| k || ψ–dilaton coupling inside e&amp;lt;sup&amp;gt;kψ&amp;lt;/sup&amp;gt;&lt;br /&gt;
|-&lt;br /&gt;
| e&amp;lt;sup&amp;gt;kψ&amp;lt;/sup&amp;gt; || Effective coupling factor; makes the fine-structure &amp;quot;constant&amp;quot; ψ-dependent&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
== Term-by-term reading of the action ==&lt;br /&gt;
&lt;br /&gt;
=== Term 1: √(−g̃) · R̃/(16π G̃) — 5D Einstein–Hilbert gravity ===&lt;br /&gt;
&lt;br /&gt;
Literally Einstein&amp;#039;s gravity, one dimension up. Varying with respect to g̃&amp;lt;sub&amp;gt;MN&amp;lt;/sub&amp;gt; gives the 5D Einstein equations G̃&amp;lt;sub&amp;gt;MN&amp;lt;/sub&amp;gt; = 8π G̃ T&amp;lt;sub&amp;gt;MN&amp;lt;/sub&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
The Kaluza–Klein &amp;quot;magic&amp;quot; is hidden in the structure of R̃: when the metric is split as below, R̃ automatically contains a 4D Einstein–Hilbert piece, a Maxwell-like F&amp;lt;sub&amp;gt;μν&amp;lt;/sub&amp;gt;F&amp;lt;sup&amp;gt;μν&amp;lt;/sup&amp;gt; piece, and a dilaton-kinetic piece. Pure 5D gravity &amp;#039;&amp;#039;produces&amp;#039;&amp;#039; electromagnetism on dimensional reduction.&lt;br /&gt;
&lt;br /&gt;
=== Term 2: −½ g̃&amp;lt;sup&amp;gt;MN&amp;lt;/sup&amp;gt; ∂&amp;lt;sub&amp;gt;M&amp;lt;/sub&amp;gt;ψ ∂&amp;lt;sub&amp;gt;N&amp;lt;/sub&amp;gt;ψ — Kinetic energy of ψ ===&lt;br /&gt;
&lt;br /&gt;
Standard scalar-field kinetic term. The negative sign in mostly-plus signature ensures positive energy density. Variation produces the wave operator □ψ.&lt;br /&gt;
&lt;br /&gt;
After compactification: −½ g&amp;lt;sup&amp;gt;μν&amp;lt;/sup&amp;gt; ∂&amp;lt;sub&amp;gt;μ&amp;lt;/sub&amp;gt;ψ ∂&amp;lt;sub&amp;gt;ν&amp;lt;/sub&amp;gt;ψ plus a tower of [[Kaluza-Klein_Modes|Kaluza–Klein modes]] indexed by integer n with masses m&amp;lt;sub&amp;gt;n&amp;lt;/sub&amp;gt;&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt; = m&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt; + (n/L)&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
=== Term 3: −½ m&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt;ψ&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt; — Mass term ===&lt;br /&gt;
&lt;br /&gt;
Quadratic in ψ. Sets the [[Yukawa_Potential|Yukawa range]] of static solutions to 1/m.&lt;br /&gt;
&lt;br /&gt;
* m → 0: massless field, propagates at c, infinite range.&lt;br /&gt;
* m &amp;gt; 0: exponential decay e&amp;lt;sup&amp;gt;−mr&amp;lt;/sup&amp;gt; at long distance — the rigorous basis for ψ-shielding.&lt;br /&gt;
&lt;br /&gt;
=== Term 4: −(λ/4) ψ&amp;lt;sup&amp;gt;4&amp;lt;/sup&amp;gt; — Quartic self-interaction ===&lt;br /&gt;
&lt;br /&gt;
Stabilising. With λ &amp;gt; 0, ψ cannot run away to infinity. This term supports [[Soliton_Solutions_of_Psi_Field|soliton solutions]] — self-sustaining, localised lumps of ψ that hold their shape — providing the rigorous mathematical basis for &amp;quot;thought-forms&amp;quot; and stable energy constructs.&lt;br /&gt;
&lt;br /&gt;
The same nonlinearity generates the collective-amplification N&amp;lt;sup&amp;gt;4&amp;lt;/sup&amp;gt; scaling in energy density when N practitioners phase-synchronise.&lt;br /&gt;
&lt;br /&gt;
=== Term 5: −¼ e&amp;lt;sup&amp;gt;kψ&amp;lt;/sup&amp;gt; F̃&amp;lt;sub&amp;gt;MN&amp;lt;/sub&amp;gt;F̃&amp;lt;sup&amp;gt;MN&amp;lt;/sup&amp;gt; — Dilaton-coupled EM ===&lt;br /&gt;
&lt;br /&gt;
The e&amp;lt;sup&amp;gt;kψ&amp;lt;/sup&amp;gt; prefactor is what makes psionics distinctive. When ψ rises, the effective electromagnetic coupling changes locally — this is the rigorous mechanism for &amp;quot;intent affecting physical constants&amp;quot;. The effect is local, small, and real.&lt;br /&gt;
&lt;br /&gt;
Without the e&amp;lt;sup&amp;gt;kψ&amp;lt;/sup&amp;gt; factor this term is just Maxwell&amp;#039;s action in 5D.&lt;br /&gt;
&lt;br /&gt;
=== Term 6: J&amp;lt;sub&amp;gt;ψ&amp;lt;/sub&amp;gt; ψ — Source coupling ===&lt;br /&gt;
&lt;br /&gt;
Direct linear coupling of an external &amp;quot;current&amp;quot; J&amp;lt;sub&amp;gt;ψ&amp;lt;/sub&amp;gt; to ψ. J&amp;lt;sub&amp;gt;ψ&amp;lt;/sub&amp;gt; encodes the practitioner&amp;#039;s brain (via coherent neural firing) or a device output. Variation with respect to ψ places J&amp;lt;sub&amp;gt;ψ&amp;lt;/sub&amp;gt; on the RHS of the field equation.&lt;br /&gt;
&lt;br /&gt;
== Derivation of the 4D effective theory ==&lt;br /&gt;
&lt;br /&gt;
=== Step 1: Kaluza–Klein ansatz ===&lt;br /&gt;
&lt;br /&gt;
Write the 5D metric in block form:&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math display=&amp;quot;block&amp;quot;&amp;gt;\tilde{g}_{MN} = \begin{pmatrix} g_{\mu\nu} + \phi^2 A_\mu A_\nu &amp;amp; \phi^2 A_\mu \\ \phi^2 A_\nu &amp;amp; \phi^2 \end{pmatrix}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
This is a parameterisation, not an imposition.&lt;br /&gt;
&lt;br /&gt;
=== Step 2: Compactify the fifth dimension ===&lt;br /&gt;
&lt;br /&gt;
Assume:&lt;br /&gt;
&lt;br /&gt;
# x&amp;lt;sup&amp;gt;5&amp;lt;/sup&amp;gt; is periodic with period 2πL (a circle).&lt;br /&gt;
# All fields are independent of x&amp;lt;sup&amp;gt;5&amp;lt;/sup&amp;gt; to leading order — the [[Cylinder_Condition|cylinder condition]] / zero-mode approximation.&lt;br /&gt;
&lt;br /&gt;
=== Step 3: Integrate out x&amp;lt;sup&amp;gt;5&amp;lt;/sup&amp;gt; ===&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math display=&amp;quot;block&amp;quot;&amp;gt;\int d^5x \;\longrightarrow\; (2\pi L) \int d^4x&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Pull the 2πL factor out and redefine the 4D Newton constant: G = G̃/(2πL).&lt;br /&gt;
&lt;br /&gt;
=== Step 4: Resulting 4D action ===&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math display=&amp;quot;block&amp;quot;&amp;gt;S_{4D} = \int d^4x \, \sqrt{-g} \, \phi \left[ \frac{R}{16\pi G} - \tfrac{1}{4} \phi^2 F_{\mu\nu} F^{\mu\nu} - \tfrac{1}{2} \partial^\mu \psi \, \partial_\mu \psi - \tfrac{1}{2} m^2 \psi^2 - \frac{\lambda}{4} \psi^4 + J_\psi \psi - \frac{e^{k\psi}}{4} F_{\mu\nu} F^{\mu\nu} \right]&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Gravity (R term), electromagnetism (F&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt; term), and the ψ field all emerge from one 5D action. ϕ (the dilaton) becomes another scalar field — in many models it is stabilised at a fixed value, but in general it must be treated as dynamical.&lt;br /&gt;
&lt;br /&gt;
== Derivation of the ψ field equation ==&lt;br /&gt;
&lt;br /&gt;
The Euler–Lagrange equation for ψ:&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math display=&amp;quot;block&amp;quot;&amp;gt;\partial_\mu \left[ \frac{\partial \mathcal{L}}{\partial(\partial_\mu \psi)} \right] - \frac{\partial \mathcal{L}}{\partial \psi} = 0&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
Substituting from the 4D Lagrangian (and absorbing dilaton ϕ into normalisation):&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math display=&amp;quot;block&amp;quot;&amp;gt;\Box \psi - m^2 \psi - \lambda \psi^3 = \alpha \, F_{\mu\nu} F^{\mu\nu} + J_\psi&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
where α arises from expanding e&amp;lt;sup&amp;gt;kψ&amp;lt;/sup&amp;gt; ≈ 1 + kψ + ½(kψ)&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt; + … and absorbing the linear-in-ψ piece into the effective F&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt; source.&lt;br /&gt;
&lt;br /&gt;
This is the master ψ equation appearing on [[Psionics]] §&amp;quot;Psionic Scalar Field Equation (4D)&amp;quot;.&lt;br /&gt;
&lt;br /&gt;
== Derivation of the non-relativistic Yukawa equation ==&lt;br /&gt;
&lt;br /&gt;
In the static (∂&amp;lt;sub&amp;gt;t&amp;lt;/sub&amp;gt;ψ = 0), weak-field, non-relativistic limit:&lt;br /&gt;
&lt;br /&gt;
* Drop the time derivative in □ψ → □ → −∇&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt;.&lt;br /&gt;
* Drop the λψ&amp;lt;sup&amp;gt;3&amp;lt;/sup&amp;gt; term (linearisation).&lt;br /&gt;
* Drop the F&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt; term (no rapidly-varying EM).&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math display=&amp;quot;block&amp;quot;&amp;gt;\nabla^2 \psi - m^2 \psi = -4\pi G_\psi \, \rho_\psi&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
&amp;#039;&amp;#039;&amp;#039;Point-source solution:&amp;#039;&amp;#039;&amp;#039;&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math display=&amp;quot;block&amp;quot;&amp;gt;\psi(r) = -\frac{G_\psi M_\psi}{r} \, e^{-mr}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
* m = 0 → ordinary 1/r Newtonian/Coulombic potential.&lt;br /&gt;
* m &amp;gt; 0 → exponentially screened beyond r ~ 1/m.&lt;br /&gt;
&lt;br /&gt;
This is the equation appearing on [[Psionics]] §&amp;quot;Non-Relativistic Limit&amp;quot; with full provenance.&lt;br /&gt;
&lt;br /&gt;
== Sanity checks (limits that recover known physics) ==&lt;br /&gt;
&lt;br /&gt;
{| class=&amp;quot;wikitable&amp;quot; style=&amp;quot;width:100%;&amp;quot;&lt;br /&gt;
! Limit !! Recovered theory !! Status&lt;br /&gt;
|-&lt;br /&gt;
| ψ = 0, F = 0 || Pure 5D vacuum Einstein gravity || ✓&lt;br /&gt;
|-&lt;br /&gt;
| ψ = 0, compactify || 4D Maxwell + Einstein (the original [[Theodor_Kaluza|Kaluza]] 1921 / [[Oskar_Klein|Klein]] 1926 construction) || ✓&lt;br /&gt;
|-&lt;br /&gt;
| F = 0, m = 0, λ = 0, J&amp;lt;sub&amp;gt;ψ&amp;lt;/sub&amp;gt; = 0 || Massless free scalar in 5D ([[Wesson_Induced_Matter_Theory|Wesson-style]]) || ✓&lt;br /&gt;
|-&lt;br /&gt;
| Non-relativistic + static + linear || [[Yukawa_Potential|Yukawa equation]] || ✓&lt;br /&gt;
|-&lt;br /&gt;
| Non-relativistic + static + massless || Poisson equation ∇&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt;ψ = source || ✓&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
If any of these fails, the derivation is wrong. See [[Sanity_Check_Limits]] for the full programme.&lt;br /&gt;
&lt;br /&gt;
== Experimental Status ==&lt;br /&gt;
&lt;br /&gt;
The 5D action principle is theoretical; what is experimentally tested is its consequences. The closest direct probes:&lt;br /&gt;
&lt;br /&gt;
* [[Compactification_in_Kaluza-Klein|Bounds on extra-dimension size]] from LHC missing-energy searches and short-range gravity (Eöt-Wash group) constrain L. For L below current bounds, the framework is consistent.&lt;br /&gt;
* [[Sanity_Check_Limits|Sanity-check reductions]] are arithmetic and pass by construction.&lt;br /&gt;
* [[Psi_Field|ψ-field phenomenology]] (Yukawa shielding ranges, anomalous biophoton coherence, [[Cooper_Pair_Mass_Anomaly|Tate experiment]], [[Gravitomagnetic_London_Moment|Tajmar 2007]]) is consistent with predictions but not yet a unique fit — degenerate with other extensions of GR.&lt;br /&gt;
&lt;br /&gt;
== References ==&lt;br /&gt;
&lt;br /&gt;
* Kaluza, T. (1921). &amp;quot;Zum Unitätsproblem der Physik.&amp;quot; &amp;#039;&amp;#039;Sitzungsberichte der Königlich Preussischen Akademie der Wissenschaften (Berlin)&amp;#039;&amp;#039;: 966–972.&lt;br /&gt;
* Klein, O. (1926). &amp;quot;Quantentheorie und fünfdimensionale Relativitätstheorie.&amp;quot; &amp;#039;&amp;#039;Zeitschrift für Physik&amp;#039;&amp;#039; 37: 895–906.&lt;br /&gt;
* Klein, O. (1926). &amp;quot;The Atomicity of Electricity as a Quantum Theory Law.&amp;quot; &amp;#039;&amp;#039;Nature&amp;#039;&amp;#039; 118: 516.&lt;br /&gt;
* Overduin, J. M., Wesson, P. S. (1997). &amp;quot;Kaluza–Klein gravity.&amp;quot; &amp;#039;&amp;#039;Physics Reports&amp;#039;&amp;#039; 283: 303–378.&lt;br /&gt;
* Wesson, P. S. (1999). &amp;#039;&amp;#039;Space–Time–Matter: Modern Kaluza–Klein Theory.&amp;#039;&amp;#039; World Scientific.&lt;br /&gt;
* Appelquist, T., Chodos, A., Freund, P. G. O. (1987). &amp;#039;&amp;#039;Modern Kaluza–Klein Theories.&amp;#039;&amp;#039; Addison-Wesley.&lt;br /&gt;
&lt;br /&gt;
== See Also ==&lt;br /&gt;
&lt;br /&gt;
* [[Psionics]] — canonical 4D equation set, with this page as its derivation source.&lt;br /&gt;
* [[Psi_Field]] — the field whose dynamics this action governs.&lt;br /&gt;
* [[Kaluza-Klein_Unification]] — historical and physical motivation for the 5D construction.&lt;br /&gt;
* [[Higher-Dimensional_Physics]] — broader landscape of higher-D theories.&lt;br /&gt;
* [[Compactification_in_Kaluza-Klein]] — what &amp;quot;the 5th dimension is small&amp;quot; really means.&lt;br /&gt;
* [[Cylinder_Condition]] — the zero-mode approximation used in §&amp;quot;Step 2&amp;quot;.&lt;br /&gt;
* [[Dilaton]] — the ϕ scalar field of §&amp;quot;Term 1&amp;quot;.&lt;br /&gt;
* [[Wesson_Induced_Matter_Theory]] — alternative interpretation of §&amp;quot;Term 1&amp;quot; with a non-compact extra dimension.&lt;br /&gt;
* [[Modified_Einstein_Equations_with_Psi]] — what variation with respect to g̃&amp;lt;sub&amp;gt;MN&amp;lt;/sub&amp;gt; gives.&lt;br /&gt;
* [[Sanity_Check_Limits]] — full list of recovery checks.&lt;br /&gt;
* [[Symbol_Glossary]] — symbol-only reference.&lt;br /&gt;
&lt;br /&gt;
[[Category:Psionics]]&lt;br /&gt;
[[Category:Equations]]&lt;br /&gt;
[[Category:Higher-dimensional physics]]&lt;/div&gt;</summary>
		<author><name>JonoThora</name></author>
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