Dark Energy Models and Laws of Thermodynamics in Bianchi I Model

TL;DR

This study examines the validity of thermodynamic laws in a Bianchi I universe filled with dark matter and dark energy, confirming the laws on the apparent horizon but not on a fixed-radius horizon for two dark energy models.

Contribution

It investigates thermodynamic laws in anisotropic cosmological models with generalized holographic and Ricci dark energy, highlighting conditions for their validity.

Findings

Thermodynamic laws hold on the apparent horizon for both models.

Laws do not hold on a fixed-radius horizon for either model.

First and second laws are valid on the apparent horizon but not on fixed-radius horizons.

Abstract

This paper is devoted to check validity of the laws of thermodynamics for LRS Bianchi type I universe model which is filled with combination of dark matter and dark energy. We take two types of dark energy models, i.e., generalized holographic dark energy and generalized Ricci dark energy. It is proved that the first and generalized second law of thermodynamics are valid on the apparent horizon for both the models. Further, we take fixed radius $L$ of the apparent horizon with original holographic or Ricci dark energy. We conclude that the first and generalized second laws of thermodynamics do not hold on the horizon of fixed radius $L$ for both the models.