Gravitational wave from warm inflation

TL;DR

This paper investigates the gravitational wave spectrum produced during warm inflation, analyzing its components and discussing how observational data can distinguish warm inflation from cold inflation models.

Contribution

It provides a detailed calculation of the gravitational wave spectrum in warm inflation, including thermal, quantum, and cross contributions, and discusses observational implications.

Findings

Thermal, quantum, and cross terms contribute to the gravitational wave spectrum.

Warm inflation has distinct observational signatures from cold inflation.

The paper offers insights into the stability and physical properties of warm inflation.

Abstract

A fundamental prediction of inflation is a nearly scale-invariant spectrum of gravitational wave. The features of such a signal provide extremely important information about the physics of the early universe. In this paper, we focus on several topics about warm inflation. First, we discuss the stability property about warm inflation based on nonequilibrium statistical mechanics, which gives more fundamental physical illustrations to thermal property of such model. Then, we calculate the power spectrum of gravitational waves generated during warm inflation, in which there are three components contributing to such spectrum: thermal term, quantum term and cross term combining the both. We also discuss some interesting properties about these terms and illustrate them in different panels. As a model different from cold inflation, warm inflation model has its individual properties in observational practice, so we finally give a discussion about the observational effect to distinguish it from cold inflation.