Emission of correlated photon pairs from superluminal perturbations in dispersive media

TL;DR

This paper presents a perturbative theory predicting the emission of correlated photon pairs from superluminal refractive perturbations in dispersive media, with potential for experimental observation and enhancement in fast light conditions.

Contribution

It introduces a novel theoretical framework for photon pair emission due to superluminal perturbations, including the possibility of spectrum engineering in dispersive media.

Findings

Photon pairs are emitted mainly within a Cerenkov-like cone.

Emission rate can reach up to ~0.01 photons per pulse under realistic conditions.

Fast light media can enhance photon emission by approximately ten times.

Abstract

We develop a perturbative theory that describes a superluminal refractive perturbation propagating in a dispersive medium and the subsequent excitation of the quantum vacuum zero-point fluctuations. We find a process similar to the anomalous Doppler effect: photons are emitted in correlated pairs and mainly within a Cerenkov-like cone, one on the forward and the other in backward directions. The number of photon pairs emitted from the perturbation increases strongly with the degree of superluminality and under realizable experimental conditions, it can reach up to ~0.01 photons per pulse. Moreover, it is in principle possible to engineer the host medium so as to modify the effective group refractive index. In the presence of "fast light" media, e.g. a with group index smaller than unity, a further ~10x enhancement may be achieved and the photon emission spectrum is characterized by two sharp peaks that, in future experiments would clearly identify the correlated emission of photon pairs.