A Fluctuation-Theorem Estimate for Entropy Decrease During Contraction

For microscopic decreases the suppression is mild and such events are routine. For anything macroscopic it becomes overwhelming, and for a cosmological decrease the logarithm of the probability is itself a cosmological-scale negative number. A fluctuation origin for a low-entropy branch is not merely unlikely; it is suppressed beyond any scale at which the word improbable retains meaning. 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: cases.one_kB.dS_kB = 1; cases.one_kB.log10_probability_ratio = -0.434; cases.photon_gas_cm3.dS_kB = 1.00e+15; cases.photon_gas_cm3.log10_probability_ratio = -4.34e+14; cases.one_mole_gas.dS_kB = 1.00e+23; cases.one_mole_gas.log10_probability_ratio = -4.34e+22; cases.stellar.dS_kB = 1.00e+60. The study is simulated and computed, not measured, and its conclusions are stated at the precision the stated assumptions support.