A thermodynamic motivation for dark energy

TL;DR

This paper suggests that the discovery of cosmic acceleration aligns with thermodynamic principles, implying dark energy or modified gravity theories should have been anticipated and are compatible with observations.

Contribution

It provides a thermodynamic perspective that predicts dark energy's existence based on the generalized second law and equilibrium considerations.

Findings

Cosmic acceleration can be explained through thermodynamic laws.

Models satisfying thermodynamic criteria align with observational data.

Dark energy or modified gravity theories are theoretically expected.

Abstract

It is argued that the discovery of cosmic acceleration could have been anticipated on thermodynamic grounds, namely, the generalized second law and the approach to equilibrium at large scale factor. Therefore, the existence of dark energy -or equivalently, some modified gravity theory- should have been expected. In general, cosmological models that satisfy the above criteria show compatibility with observational data.