Photon generation and entanglement in a double superconducting cavity

TL;DR

This paper investigates photon creation and entanglement in a double superconducting cavity using circuit QED, analyzing spectral properties, photon generation, and entanglement dynamics under various initial conditions.

Contribution

It introduces a novel approach to simulate a double cavity in circuit QED and explores entanglement generation between uncoupled cavities after photon creation.

Findings

Photon spectrum varies with dielectric susceptibility and cavity lengths.

Cavities become entangled through dynamical Casimir effect in different initial states.

Entanglement can be enhanced or diminished depending on initial photon conditions.

Abstract

We study the dynamical Casimir effect in a double superconducting cavity in a circuit quantum electrodynamics architecture. Parameters in the quantum circuit are chosen in such a way the superconducting cavity can mimic a double cavity, formed by two perfectly conducting outer walls and a dielectric one, with arbitrary permittivity separating both halves. We undertake a spectral analysis of the cavity, showing that the spectrum varies significantly depending on the values of the susceptibility of the dielectric mirror and the relative lengths of both cavities. We study the creation of photons when the walls oscillate harmonically with a small amplitude. Furthermore, we explore the possibility of entangling two uncoupled cavities, starting from a symmetric double cavity and having both of its halves become uncoupled at a later given instant. We consider both cases: (i) when the field is initially in a vacuum state and (ii) the situation in which photon creation via the dynamical Casimir effect has already taken place. We show that the cavities become entangled in both cases but, in the latter, the quantum correlation between individual modes can be greatly increased at the cost of diminishing the entanglement between most pairs of modes.