Thermodynamics of the SGCC Bounce: Bekenstein–Hawking Entropy Conservation, the Horizon Budget, and the Refutation of Heat Death v2 — Erratum: torsion amplitude calibration

ERRATUM (v2, 2026-07-04) — Correction to the torsion amplitude |T0| calibration (Appendix D). A review of the torsion amplitude calibration revealed three corrections affecting the quantitative interpretation of the bounce, without altering the Riemann-Cartan framework or the central heat-death refutation result. (1) BOUNCE REGIME. The ad-hoc value |T0| = 1e-4 H0² places the bounce at abounce ~ 0. 04-0. 07 (z ~ 14-22), i. e. AFTER CMB recombination (z=1100) and Big Bang Nucleosynthesis (BBN). This regime is observationally excluded. The binding bound is not the Solar System limit (|T0|. The standard Einstein-Cartan-Sciama-Kibble spin-fluid formalism uses the QUADRATIC term (Weyssenhoff; Poplawski 2016, ApJ 832, 96), independent of orientation coherence. More fundamentally, the physical source of the bounce torsion is the primordial fermionic fluid at densities > 1e45 kg/m³, not the SMBH population, which forms ~18 orders of magnitude in scale factor AFTER the bounce. The value |T0|SMBH ~ 8. 6e-41 H0² must be interpreted as a scale analogy of the spin-torsion coupling in the accessible regime, NOT as the causal source of the bounce. WHAT DOES NOT CHANGE. The Riemann-Cartan framework, the stiff scaling (a0/a) ⁶, the result that any bounce-compatible torsion term is undetectable in the CMB by construction (scale decoupling), and consistency with the null Q22xCMB cross-correlation limits (Papers VIII/IX) remain valid and are in fact strengthened: the CMB null is trivial by construction, not a constraint on epsₚv. The final sentence of the original abstract below (". . . providing a theoretical justification for the null CMB result. . . 36 orders below the Solar System bound") is superseded by points (1) and (3) above: |T0|SMBH is a scale analogy, not a first-principles source calibration, and the CMB null is trivial rather than a constraint. A complete treatment of the viability window and the observational anchoring of the SMBH population within the natural cosmological selection framework (Smolin 1992) + torsional bounce (Poplawski) is presented in separate work (in preparation). ───────────────────────────────────────────────── ORIGINAL ABSTRACT (v1, unchanged): We present a complete thermodynamic analysis of the Self-Generated Cyclic Cosmology (SGCC) bounce within the Riemann–Cartan framework. Using the Bekenstein–Hawking entropy of the supermassive black hole (SMBH) population as the primary thermodynamic observable, we demonstrate that the classical heat death of the universe is not a physical fate within the SGCC framework, but a limit that is never reached because the torsional bounce interrupts the cosmic timeline 81 orders of magnitude before Hawking evaporation completes. We compute six independent thermodynamic quantities. (i) The Hawking evaporation timescale tauH ~ 3. 6×10⁹1 yr for a median SMBH mass of 1. 2×10⁸ Mₛun, compared to a typical bounce time tbounce ~ 7 Gyr, giving tauH/tbounce ~ 2. 6×10⁸1. (ii) Area conservation through the Kruskal throat: DeltaSBH/SBH < 10^-13, confirming the horizon area as a topological invariant across the bounce. (iii) The horizon budget: the entropy density s = SBH/Vₕorizon is 10²–10³ times higher at the bounce than today, demonstrating that the universe is far from thermodynamic equilibrium at the bounce. (iv) Pre-bounce accretion: DeltaM/M < 10^-15 — mass and entropy are conserved to numerical precision. (v) The adiabatic cycle invariant J = SBH/Sᵣad = 3. 617×10^-16, constant across the bounce, establishes thermodynamic self-consistency of the SGCC cycle. (vi) The von Neumann entropy of the torsion field SᵥN ~ 10⁴2 J K^-1 quantifies the information encoded in the spin-memory mechanism of Paper B.