Manipulating lightcone fluctuations in an analogue cosmic string

TL;DR

This paper explores how metamaterials can simulate cosmic string effects on light, allowing manipulation of lightcone fluctuations in laboratory settings to observe quantum gravitational analogues.

Contribution

It introduces a metamaterial-based analogue model of a cosmic string that enables control over lightcone fluctuation effects through dielectric properties.

Findings

Flight time variance is proportional to the parameter $ u$ of the cosmic string.

Metamaterials can be designed to mimic cosmic strings with large $ u$ values.

Laboratory experiments could observe quantum gravitational effects via this analogue model.

Abstract

We study the flight time fluctuations in an anisotropic medium inspired by a cosmic string with an effective fluctuating refractive index caused by fluctuating vacuum electric fields, which are analogous to the lightcone fluctuations due to fluctuating spacetime metric when gravity is quantized. The medium can be realized as a metamaterial that mimics a cosmic string in the sense of transformation optics. For a probe light close to the analogue string, the flight time variance is $\nu$ times that in a normal homogeneous and isotropic medium, where $\nu$ is a parameter characterizing the deficit angle of the spacetime of a cosmic string. The parameter $\nu$, which is always greater than unity for a real cosmic string, is determined by the dielectric properties of the metamaterial for an analogue string. Therefore, the flight time fluctuations of a probe light can be manipulated by changing the electric permittivity and magnetic permeability of the analogue medium. We argue that it seems possible to fabricate a metamaterial that mimics a cosmic string with a large $\nu$ in laboratory so that a currently observable flight time variance might be achieved.