Relic gravitational waves and the generalized second law

TL;DR

This paper examines how the generalized second law of thermodynamics applies to the current accelerated expansion of the universe, focusing on the entropy of matter and relic gravitational waves.

Contribution

It demonstrates that the generalized second law holds if the entropy density of gravitational waves meets specific conditions during cosmic acceleration.

Findings

Entropy of matter and gravitational waves decreases inside the horizon.

The generalized second law is satisfied under certain entropy density conditions.

Relic gravitational waves' entropy plays a crucial role in thermodynamic consistency.

Abstract

The generalized second law of gravitational thermodynamics is applied to the present era of accelerated expansion of the Universe. In spite of the fact that the entropy of matter and relic gravitational waves inside the event horizon diminish, the mentioned law is fulfilled provided that the expression for the entropy density of the gravitational waves satisfies a certain condition.