The generalized second law of thermodynamics and cosmological decoherence

TL;DR

This paper demonstrates that considering cosmological decoherence preserves the validity of the generalized second law of thermodynamics in a fluctuating de Sitter universe, highlighting decoherence's fundamental role.

Contribution

It shows that cosmological decoherence ensures the generalized second law remains valid despite quantum fluctuations in a de Sitter universe.

Findings

The generalized second law appears violated without decoherence.

Including decoherence restores the law's validity.

Supports decoherence as essential for classical universe emergence.

Abstract

We pointed out that the generalized second law of thermodynamics on a de Sitter universe whose energy density stochastically fluctuates due to quantum fluctuations is seemingly violated. We have shown that even in such a case, the generalized second law is unviolated by taking cosmological decoherence into account. It has been well known that the decoherence is necessary to give a reasonable reason why our universe looks classical. Our proposal can support the importance of decoherence from another aspect, i.e. the generalized second law of thermodynamics.