English

Modified cosmology from the thermodynamics of apparent horizon

General Relativity and Quantum Cosmology 2022-12-14 v1

Abstract

In the realm of the Bekenstein-Hawking entropy, the thermodynamics of apparent horizon bridges with the usual FLRW (Friedmann-Lema\^{i}tre-Robertson-Walker) equation only for a special case where the matter field is given by a perfect fluid having equation of state (EoS) parameter =1= -1, i.e p=ρp = -\rho with ρ\rho and pp represent the energy density and the pressure of the fluid, respectively. To include the case pρp \neq -\rho, we consider the modification of the Bekenstein-Hawking entropy in the present work. In particular, we develop an entropy function that leads to the usual FLRW equations, for a generalgeneral EoS of the matter fluid given by p=wρp = w\rho, directly from the thermodynamics of the apparent horizon. The newly developed entropy acquires a correction over the Bekenstein-Hawking entropy and differs from the known entropies like the Tsallis, R\'{e}nyi, Barrow, Sharma-Mittal, Kaniadakis, and Loop Quantum Gravity entropies proposed so far. Based on this finding, we examine how the Friedmann equations of the apparent horizon cosmology are accordingly modified if one starts with a general entropy depending on the Bekenstein-Hawking entropy. This results in some interesting cosmological consequences during the early and late stages of the universe.

Keywords

Cite

@article{arxiv.2211.02822,
  title  = {Modified cosmology from the thermodynamics of apparent horizon},
  author = {Shin'ichi Nojiri and Sergei D. Odintsov and Tanmoy Paul},
  journal= {arXiv preprint arXiv:2211.02822},
  year   = {2022}
}

Comments

Physics Letters B (PLB) accepted