A Model for Lightcone Fluctuations due to Stress Tensor Fluctuations

TL;DR

This paper models quantum lightcone fluctuations caused by stress tensor fluctuations, using nonlinear dielectric materials to simulate spacetime effects and estimate the probability of large quantum fluctuation events.

Contribution

It introduces a novel model linking electric field fluctuations in nonlinear dielectrics to spacetime stress tensor fluctuations, providing a way to estimate fluctuation probabilities.

Findings

Flight time variations depend on squared electric field fluctuations.

The model relates material geometry to fluctuation sampling functions.

Large fluctuation probabilities can be estimated from the model.

Abstract

We study a model for quantum lightcone fluctuations in which vacuum fluctuations of the electric field and of the squared electric field in a nonlinear dielectric material produce variations in the flight times of probe pulses. When this material has a non-zero third order polarizability, the flight time variations arise from squared electric field fluctuations, and are analogous to effects expected when the stress tensor of a quantized field drives passive spacetime geometry fluctuations. We also discuss the dependence of the squared electric field fluctuations upon the geometry of the material, which in turn determines a sampling function for averaging the squared electric field along the path of the pulse. This allows us to estimate the probability of especially large fluctuations, which is a measure of the probability distribution for quantum stress tensor fluctuations.