Classical enhancement of quantum vacuum fluctuations

TL;DR

This paper introduces a method to amplify quantum vacuum fluctuations using a classical field, potentially making quantum effects more observable in experiments involving nonlinear dielectrics.

Contribution

It presents a novel mechanism for enhancing quantum vacuum fluctuations through classical fields in nonlinear materials, with a practical example demonstrating significant amplification.

Findings

Classical fields can increase vacuum fluctuation effects by an order of magnitude.

Vacuum electric field fluctuations cause measurable light speed fluctuations.

The proposed method could improve detection of quantum gravity analogs.

Abstract

We propose a mechanism for the enhancement of vacuum fluctuations by means of a classical field. The basic idea is that if an observable quantity depends quadratically upon a quantum field, such as the electric field, then the application of a classical field produces a cross term between the classical and quantum fields. This cross term may be significantly larger than the purely quantum part, but also undergoes fluctuations driven by the quantum field. We illustrate this effect in a model for lightcone fluctuations involving pulses in a nonlinear dielectric. Vacuum electric field fluctuations produce fluctuations in the speed of a probe pulse, and form an analog model for quantum gravity effects. If the material has a nonzero third-order susceptibility, then the fractional light speed fluctuations are proportional to the square of the fluctuating electric field. Hence the application of a classical electric field can enhance the speed fluctuations. We give an example where this enhancement can be an increase of one order of magnitude, increasing the possibility of observing the effect.