Thermal fluctuations of bouncing cosmology revisited

TL;DR

This paper revisits thermal fluctuations in bouncing cosmology, incorporating the Unruh effect, and finds corrections to the power spectrum that suggest a blue tilt at large wave numbers, aligning with vacuum initial conditions.

Contribution

It introduces the impact of the Unruh effect on thermal fluctuations in bouncing cosmology, providing corrected power spectrum predictions.

Findings

Power spectrum dependence on k is corrected by the Unruh effect.

A blue tilt appears at large k in the power spectrum.

Results are consistent with vacuum initial conditions.

Abstract

In this note, we revisit the thermal fluctuations generated during bouncing cosmology, taking Unruh effect into account. We find that due to the additional effect on temperature, the dependence of power spectrum on $k$ will get corrected with an indication of blue tilt at large $k$ region, which is in consistent with the case of vacuum initial conditions.