Microwave Background Entropy Compared with the Temperature Ceiling at the Bounce

The ratio is unity at the precision of the arithmetic, confirming that adiabatic transport through a density-limited bounce neither creates nor destroys photon entropy. Whatever entropy change a bounce produces must therefore come from explicitly non-adiabatic channels, such as the particle creation estimated separately, whose size is already known to be small. The computation is performed from stated assumptions in a density-limited bounce, in which the neutron-branch limit density sets a maximum density, a finite bounce temperature, and a minimum horizon size. Headline values from the deposited calculation are: T_bounce_K = 3.28e+22; S_cmb_today_kB = 5.28e+89; V_bounce_m3 = 2.05e+14; S_same_comoving_at_bounce_kB = 5.28e+89; ratio_bounce_to_today = 1; adiabatic_invariant_check = 3.29e+17. The study is simulated and computed, not measured, and its conclusions are stated at the precision the stated assumptions support.