Thermodynamics of cosmological horizons in $f(T)$ gravity

TL;DR

This paper investigates the thermodynamics of cosmological apparent horizons within $f(T)$ gravity, demonstrating dual equilibrium and non-equilibrium formulations and conditions under which the second law holds.

Contribution

It establishes a dual thermodynamic framework for $f(T)$ gravity analogous to $f(R)$ gravity and analyzes the second law's validity in this context.

Findings

Dual equilibrium and non-equilibrium thermodynamic descriptions for $f(T)$ gravity.

Second law of thermodynamics can be satisfied when horizon and universe temperatures are equal.

Similar thermodynamic structure between $f(T)$ and $f(R)$ gravity.

Abstract

We explore thermodynamics of the apparent horizon in $f(T)$ gravity with both equilibrium and non-equilibrium descriptions. We find the same dual equilibrium/non-equilibrium formulation for $f(T)$ as for $f(R)$ gravity. In particular, we show that the second law of thermodynamics can be satisfied for the universe with the same temperature of the outside and inside the apparent horizon.