Experiments / V2.11
V2.11
Field Equations COMPLETE

Clausius Relation from Entanglement First Law

Experiment V2.11: Clausius Relation from Entanglement First Law

Status: COMPLETE

Goal

Derive the Clausius relation δQ = T dS from the entanglement first law, using capacity-derived quantities only (V2.03 entropy, V2.04 temperature).

Key Difference from V1

V1 Exp 4-5 (circular): Defined entropy as σ_S = λ_S × C_t (fitted) and heat as q ~ χ_Q × ∇C_t (fitted). Then checked if δQ ≈ T dS with ξ fitted to match 4πG/c². This is regression fitting, not derivation.

V2 Exp 11 (non-circular): Entropy is derived from QFT (V2.03), temperature from the slope law (V2.04), and the Clausius relation follows from the entanglement first law — a theorem of quantum mechanics.

The Derivation (8 Steps)

Step 1: Thermal Identity

For Bose-Einstein occupation n̄ = 1/(e^{ω/T} - 1):

ds/dn̄ = ln(1 + 1/n̄) = ln(e^{ω/T}) = ω/T

Verified to machine precision (~10⁻¹⁶) across all temperatures.

Step 2: Entanglement First Law

The modular Hamiltonian eigenvalue at frequency ω is k(ω) = ω/T. Therefore:

δ⟨K⟩ = ∫ k(ω) δn̄ ρ(ω) dω = ∫ (ω/T) δn̄ ρ(ω) dω

δS   = ∫ s'(n̄) δn̄ ρ(ω) dω = ∫ (ω/T) δn̄ ρ(ω) dω

These are IDENTICAL by Step 1. The entanglement first law δ⟨K⟩ = δS holds EXACTLY (not just at first order) for thermal states.

Verified: residual < 10⁻¹³ for all T tested.

Step 3: Capacity-Derived Temperature

From V2.04: Q_t = C_Q × T where C_Q = (4Ac₃)^{1/3}.

Therefore: T = Q_t / C_Q = κ/(2π).

Step 4: Capacity-Derived Entropy

From V2.03 (1+1D): S/L = (π/(6C_Q)) × Q_t = (π/6) × T.

Step 5: The Clausius Relation

δQ = δ⟨H_R⟩ = T × δ⟨K⟩ = T × δS

Since K = H_R / T, we have δ⟨H_R⟩ = T × δ⟨K⟩ = T × δS.

This IS the Clausius relation δQ = T dS.

Results

Phase 1: Thermal Identity (5/5 PASS)

| T | max |ds/dn̄ - ω/T| / (ω/T) | |------|-------------------------------| | 0.1 | 5.6 × 10⁻¹⁶ | | 0.5 | 6.9 × 10⁻¹⁶ | | 1.0 | 6.9 × 10⁻¹⁶ | | 2.0 | 6.9 × 10⁻¹⁶ | | 5.0 | 6.9 × 10⁻¹⁶ |

The identity holds to floating-point precision.

Phase 2: Entanglement First Law (6/6 PASS)

| T | δ⟨K⟩ | δS | |δ⟨K⟩ - δS| / |δS| | |------|-----------|-----------|---------------------| | 0.1 | 2.367e-5 | 2.367e-5 | 7.1 × 10⁻¹⁴ | | 0.5 | 1.183e-4 | 1.183e-4 | 7.1 × 10⁻¹⁴ | | 1.0 | 2.367e-4 | 2.367e-4 | 7.1 × 10⁻¹⁴ | | 2.0 | 4.734e-4 | 4.734e-4 | 7.1 × 10⁻¹⁴ | | 5.0 | 1.183e-3 | 1.183e-3 | 7.1 × 10⁻¹⁴ |

Phase 3: Clausius from Capacity

Heat capacity (1+1D):

Capacity-derived: c/L = T × dS/dT = T × (π/(6C_Q)) × C_Q = πT/6 Expected: c/L = πT/6

Residual: 0.0 (EXACT match). No free parameters.

Heat capacity (3+1D):

Capacity-derived: c/V = T × (2π²/(15C_Q³)) × 3C_Q²T × C_Q = (2π²/15)T³ Expected: c/V = (2π²/15)T³

Residual: < 10⁻¹⁵. No free parameters.

Modular Hamiltonian verification:

Tδ⟨H_R⟩T × δSResidual
0.22.089e-52.089e-51.6e-13
0.51.306e-41.306e-41.6e-13
1.05.223e-45.223e-41.6e-13
2.02.089e-32.089e-31.6e-13
5.01.306e-21.306e-21.6e-13

Phase 4: Horizon Universality (ALL PASS)

Tested at κ = 0.1, 0.5, 1, 2, 5, 10, 20 in both 1+1D and 3+1D.

DimensionMax Clausius residualPass
1+1D1.6 × 10⁻¹³YES
3+1D2.5 × 10⁻¹¹YES

The Clausius relation holds universally across all horizons.

Phase 5: f(R) Gravity (ALL PASS)

αT_GRT_WaldS_from_capacityPass
0.0000.15920.15920.0833YES
0.0010.15920.15540.0814YES
0.0050.15920.14210.0744YES
0.0100.15920.12840.0672YES
0.0200.15920.10750.0563YES
0.0500.15920.07230.0379YES

The capacity framework automatically uses the Wald-corrected temperature. This means:

  • In GR: Clausius gives Einstein’s equations (V2.12)
  • In f(R): Clausius gives f(R) field equations

Non-Circularity Audit

StepDescriptionInputUses GR?
1Wightman function G+(Δτ)Background (M, g)No
2Detector response F(ω)G+(Δτ)No
3Occupation number n̄ = F/(Aω)F(ω)No
4Temperature T = Q_t/C_QF_timingNo
5Entropy S = f(Q_t)n̄ integratedNo
6Modular Hamiltonian k(ω) = ω/TNo
7Entanglement first law δ⟨K⟩ = δSK, SNo
8Clausius δQ = T dSSteps 4-7No

NO step assumes Einstein’s equations or any field equations.

What This Proves

  1. The Clausius relation is a theorem, not an assumption. It follows from the entanglement first law applied to thermal (KMS) states.

  2. Every ingredient is capacity-derived:

    • T from the slope law (V2.04)
    • S from the entropy-capacity relation (V2.03)
    • δQ from the modular Hamiltonian (QFT)
  3. The derivation is universal: It holds for all surface gravities and all metric theories of gravity (with Wald-corrected temperature).

  4. This replaces V1’s fitted Clausius with a derived one. V1 used λ_S, χ_Q, and ξ as free parameters. V2 has zero free parameters.

Connection to Phase 3 Program

ExperimentWhat it establishesStatus
V2.11δQ = T dS (Clausius from entanglement)COMPLETE
V2.12Clausius for all horizons → Einstein’s equationsNext
V2.13Non-GR backgrounds fail Clausius → GR selectedPending

V2.11 provides the first ingredient for V2.12: a non-circular Clausius relation. V2.12 will apply this to ALL local Rindler horizons (Jacobson’s argument) to derive Einstein’s field equations.

Files

FilePurposeTests
src/clausius_entanglement.pyEntanglement first law, Clausius, f(R)
tests/test_clausius_entanglement.pyValidation tests32/32
run_experiment.pyFull 5-phase experiment

Next Steps → V2.12

V2.12 will show that applying the capacity-derived Clausius relation to ALL local Rindler horizons implies Einstein’s field equations: R_ab - (1/2)R g_ab = 8πG T_ab.

The key step: show that the capacity-derived entropy is proportional to horizon area (S = A/(4G)), so that the Clausius relation constrains the Ricci tensor through the Raychaudhuri equation.