Gravitational Wave Spectrum in Inflation with Nonclassical States

TL;DR

This paper explores how nonclassical, squeezed quantum states during inflation influence the gravitational wave spectrum, highlighting the role of trans-Planckian physics and modified dispersion relations.

Contribution

It introduces the calculation of gravitational wave power spectra for nonclassical states like squeezed, squeezed coherent, and squeezed thermal states during inflation.

Findings

Nonclassical states significantly modify the gravitational wave spectrum.

Squeezed states enhance certain frequency modes.

Results provide insights into trans-Planckian effects on inflationary gravitational waves.

Abstract

The initial quantum state during inflation may evolve to a highly squeezed quantum state due to the amplification of the time-dependent parameter, $\omega_{phys}(k/a)$, which may be the modified dispersion relation in trans-Planckian physics. This squeezed quantum state is a nonclassical state that has no counterpart in the classical theory. We have considered the nonclassical states such as squeezed, squeezed coherent, and squeezed thermal states, and calculated the power spectrum of the gravitational wave perturbation when the mode leaves the horizon.