Influence of Virtual Photon Process on the Generation of Squeezed Light from Atoms in an Optical Cavity

TL;DR

This paper investigates how virtual photon processes in an atom-cavity system influence the generation of squeezed light and the potential observation of quantum phase transitions, highlighting the importance of strong coupling.

Contribution

It demonstrates that atoms in an optical cavity can produce significant squeezing and exhibit Dicke superradiant phase transition beyond the rotating wave approximation.

Findings

Squeezing is higher in the strong-coupling regime.

Dicke superradiant transition can occur in the dispersive regime.

Virtual photon processes are crucial for squeezing generation.

Abstract

We show that a collection of two-level atoms in an optical cavity beyond the rotating wave approximation and in the dispersive and strong-coupling regime constitutes a nonlinear medium and is capable of generating squeezed state of light. It is found that squeezing produced in the strong-coupling regime is significantly higher compared to that produced in the dispersive limit. On the other hand, we also show that it could be possible to observe the Dicke superradiant quantum phase transition in the dispersive regime where the vector potential term is negligible. Such a system can be an essential component of a larger quantum-communication system.