Role of qubit-cavity entanglement for switching dynamics of quantum interfaces in superconductor metamaterials

TL;DR

This paper investigates the quantum effects in a driven dissipative qubit-cavity system, revealing the importance of quantum correlations beyond mean-field approximations for understanding switching dynamics in superconducting metamaterials.

Contribution

It demonstrates the limitations of mean-field approaches and highlights the role of quantum correlations in the non-adiabatic switching regime of qubit-cavity systems.

Findings

Mean-field approximation agrees with density matrix at low driving strengths.

Quantum correlations grow and alter system behavior at higher driving strengths.

Quantum effects influence system dynamics even at weak drivings during non-adiabatic switching.

Abstract

We study quantum effects of strong driving field applied to dissipative hybrid qubit-cavity system which are relevant for a realization of quantum gates in superconducting quantum metamaterials. We demonstrate that effects of strong and non-stationary drivings have significantly quantum nature and can not be treated by means of mean-field approximation. This is shown from a comparison of steady state solution of the standard Maxwell-Bloch equations and numerical solution of Lindblad equation on a density matrix. We show that mean-field approach provides very good agreement with the density matrix solution at not very strong drivings $f<f^*$ but at $f>f^*$ a growing value of quantum correlations between fluctuations in qubit and photon sectors changes a behavior of the system. We show that in regime of non-adiabatic switching on of the driving such a quantum correlations influence a dynamics of qubit and photons even at weak $f$.