http://arxiv.org/abs/2006.09650
Cosmological adiabatic particle creation results in the generation of irreversible entropy. The evolution of the irreversible entropy is examined in a flat Friedmann–Robertson–Walker universe at late times, using a dissipative model with a power-law term (proportional to the power of the Hubble parameter $H$). In a dissipative universe, the irreversible entropy included in the Hubble volume is found to be proportional to $H^{-1}$, unlike for the Bekenstein–Hawking entropy on the horizon of the universe. In addition, the evolution of the horizon entropy is examined, extending the previous analysis of a non-dissipative universe [Phys. Rev. D 100, 123545 (2019) (arXiv:1911.08306)]. In the present model, the generalized second law of thermodynamics is always satisfied, whereas the maximization of entropy is satisfied under specific conditions. The dissipative universe should be constrained by the entropy maximization as if the universe behaves as an ordinary, isolated macroscopic system.
N. Komatsu
Thu, 18 Jun 20
41/84
Comments: [13 pages, 6 figures]