Can Lightcone Fluctuations be Probed with Cosmological Backgrounds?

TL;DR

This paper investigates whether lightcone fluctuations, a quantum gravity effect, can be detected through cosmological backgrounds like the gravitational wave background, concluding that their impact is negligible due to the flat spectrum.

Contribution

It analyzes the imprint of lightcone fluctuations on the gravitational wave background, providing a novel perspective on their detectability in cosmological observations.

Findings

Lightcone fluctuations have negligible effects on the gravitational wave background.

The flat spectrum of the GWB diminishes the potential signatures of quantum gravity effects.

Detection of lightcone fluctuations via GWB is unlikely with current observational capabilities.

Abstract

Finding signatures of quantum gravity in cosmological observations is now actively pursued both from the theoretical and the experimental side. Recent work has concentrated on finding signatures of light-cone fluctuations in the CMB. Because in inflationary scenarios a Gravitational Wave Background (GWB) is always emitted much before the CMB, we can ask, in the hypothesis where this GWB could be observed, what is the imprint of light cone fluctuations on this GWB. We show that due to the flat nature of the GWB spectrum, the effect of lightcone fluctuations are negligible.