Thermodynamical properties of metric fluctuations during inflation

TL;DR

This paper explores the thermodynamical properties of scalar metric fluctuations during inflation, revealing a negative heat capacity and linking the power spectrum to fundamental temperatures like Gibbons-Hawking and Hagedorn.

Contribution

It introduces a thermodynamical framework for inflationary metric perturbations, highlighting the negative heat capacity and temperature dependencies in a power-law universe.

Findings

Negative heat capacity indicates superexponential growth of states.

Power spectrum depends on Gibbons-Hawking and Hagedorn temperatures.

Super Hubble scales exhibit thermodynamical instabilities.

Abstract

I study a thermodynamical approach to scalar metric perturbations during the inflationary stage. In the power-law expanding universe here studied, I find a negative heat capacity as a manifestation of superexponential growing for the number of states in super Hubble scales. The power spectrum depends on the Gibbons-Hawking and Hagedorn temperatures.