Photon generation via dynamical Casimir effect in an optomechanical cavity as a closed quantum system

TL;DR

This paper analyzes photon creation in an optomechanical cavity due to the dynamical Casimir effect, considering quantum states of both the electromagnetic field and the mirror, and explores the dynamics, efficiency, and entanglement in this closed quantum system.

Contribution

It provides an analytical and numerical framework for understanding photon generation in a fully quantum optomechanical system, including effects of initial states and cavity detuning.

Findings

Photon number evolution resembles a non-harmonic quantum oscillator.

Maximum and mean photon numbers can be estimated for high energies.

Entanglement between mirror and cavity reaches calculable maxima.

Abstract

We present an analytical and numerical analysis of the particle creation in an optomechanical cavity in parametric resonance. We treat both the electromagnetic field and the mirror as quantum degrees of freedom and study the dynamical evolution as a closed quantum system. We consider different initial states and investigate the spontaneous emission of photons from phonons in the mirror. We find that for initial phononic product states the evolution of the photon number can be described as a non-harmonic quantum oscillator, providing an useful tool so as to estimate the maximum and mean number of photons produced for arbitrary high energies. The efficiency of this mechanism is further analyzed for a detuned cavity as well as the possibility of stimulating the photon production by adding some initial ones to the cavity. We also find relationships for the maximum and mean entanglement between the mirror and the wall in these states. Additionally we study coherent states for the motion of the mirror to connect this model with previous results from quantum field theory with a classical mirror. Finally we study thermal states of phonons in the wall and the equilibration process that leads to a stationary distribution.