Gravity Waves from Quantum Stress Tensor Fluctuations in Inflation

TL;DR

This paper explores how quantum stress tensor fluctuations during inflation can produce observable gravity waves with unique non-Gaussian, non-scale invariant spectra, potentially revealing transplanckian physics and constraining inflation parameters.

Contribution

It introduces a novel mechanism for gravity wave generation from quantum fluctuations, highlighting their potential observability and implications for early universe physics.

Findings

Gravity waves from quantum fluctuations are non-Gaussian and non-scale invariant.

These gravity waves depend on the total expansion factor during inflation.

Potential observability in CMB and gravity wave detectors could probe transplanckian physics.

Abstract

We consider the effects of the quantum stress tensor fluctuations of a conformal field in generating gravity waves in inflationary models. We find a non-scale invariant, non-Gaussian contribution which depends upon the total expansion factor between an initial time and the end of inflation. This spectrum of gravity wave perturbations is an illustration of a negative power spectrum, which is possible in quantum field theory. We discuss possible choices for the initial conditions. If the initial time is taken to be sufficiently early, the fluctuating gravity waves are potentially observable both in the CMB radiation and in gravity wave detectors, and could offer a probe of transplanckian physics. The fact that they have not yet been observed might be used to constrain the duration and energy scale of inflation.