Theory of non-Gaussianity in warm inflation

TL;DR

This paper develops a theoretical framework to compute the bispectrum in warm inflation, highlighting how non-Gaussianity varies with dissipation strength and proposing ways to distinguish warm from cold inflation through future observations.

Contribution

It introduces a methodology for calculating the bispectrum in warm inflation, emphasizing the impact of dissipation regimes and stochastic fluctuations on non-Gaussian features.

Findings

Non-Gaussianity amplitude depends on microscopic physics in weak dissipation.

Bispectrum shape differs significantly between weak and strong dissipation regimes.

Potential to distinguish warm and cold inflation via future non-Gaussianity data.

Abstract

The theory and methodology is developed to compute the bispectrum in warm inflation, leading to results for the non-linearity parameter and the shape of the bispectrum. Particular attention is paid to the study of the bispectrum in the regime of weak dissipation and how stochastic fluctuations affect the bispectrum. It is shown that, in contrast to the strong dissipative regime, the amplitude of non-Gaussianity is strongly dependent on the parameters governing the microscopic physics in the intermediate and weak dissipation warm inflation regimes. The most important results concern the shape of the bispectrum, which has two different, but distinct, forms in the weak and strong dissipative regimes. Comparison of shape functions could permit discrimination between the warm and cold paradigms of inflation from future precision data on primordial non-Gaussianity.