Quantum Stress Tensor Fluctuation Effects in Inflationary Cosmology

TL;DR

This paper reviews how quantum stress tensor fluctuations during inflation could significantly influence primordial density and tensor perturbations, potentially leading to observable non-Gaussian, non-scale-invariant features in the cosmic microwave background.

Contribution

It highlights the role of quantum stress tensor fluctuations as a source of primordial perturbations, emphasizing their possible dependence on the total inflationary expansion.

Findings

Quantum stress tensor fluctuations can enhance density and tensor perturbations.

These effects may produce non-Gaussian, non-scale-invariant primordial spectra.

Potential observability of these quantum effects in cosmological data.

Abstract

We review several related investigations of the effects of the quantum stress tensor of a conformal field in inflationary cosmology. Particular attention will be paid to the effects of quantum stress tensor fluctuations as a source of density and tensor perturbations in inflationary models. These effects can possibly depend upon the total expansion factor during inflation, and hence be much larger than one might otherwise expect. They have the potential to contribute a non-scale invariant and non-Gaussian component to the primordial spectrum of perturbations, and might be observable.