The Generalized Second Law of Thermodynamics in Cosmology

TL;DR

This paper explores how the generalized second law of thermodynamics constrains cosmological models, providing insights into energy conditions, entropy bounds, and non-singular solutions in string cosmology.

Contribution

It introduces a unified thermodynamic framework that links the second law to cosmological constraints and non-singular solutions, including the graceful exit from inflation.

Findings

Energy conditions restrict cosmological solutions.

Entropy bounds prevent certain singularities.

Second law supports non-singular cosmological models.

Abstract

A classical and quantum mechanical generalized second law of thermodynamics in cosmology implies constraints on the effective equation of state of the universe in the form of energy conditions, obeyed by many known cosmological solutions, and is compatible with entropy bounds which forbid certain cosmological singularities. In string cosmology the second law provides new information about the existence of non-singular solutions, and the nature of the graceful exit transition from dilaton-driven inflation.