Quantum synchronization and entanglement of dissipative qubits coupled to a resonator

TL;DR

This paper investigates how driven cavities coupled to multiple qubits exhibit quantum synchronization and entanglement, using dissipative Jaynes-Cummings models and semi-analytical approaches to understand steady states under various dissipation regimes.

Contribution

It introduces two semi-analytical methods for analyzing the steady states of driven qubit-cavity systems and demonstrates quantum synchronization and entanglement in dissipative regimes.

Findings

Entangled steady states of qubits synchronized via a driven cavity.

Effective Jaynes-Cummings model describes system dynamics under RWA.

Semi-classical approximation captures mean spin and cavity states.

Abstract

We study the properties of a driven cavity coupled to several qubits in the framework of a dissipative Jaynes-Cummings model. We show that the rotating wave approximation (RWA) allows to reduce the description of original driven model to an effective Jaynes-Cummings model with strong coupling between photons and qubits. Two semi-analytical approaches are developed to describe the steady state of this system. We first treat the weak dissipation limit where we derive perturbative series of rate equations that converge to the exact RWA steady-state except near the cavity resonance. This approach exactly describes the multi-photon resonances in the system. Then in the strong dissipation limit we introduce a semiclassical approximation which allows to reproduce the mean spin-projections and cavity state. This approach reproduces the RWA exactly in the strong dissipation limit but provides good qualitative trends even in more quantum regimes. We then focus on quantum synchronization of qubits through their coupling to the cavity. We demonstrate the entangled steady state of a pair of qubits synchronized through their interaction with a driven cavity in presence of dissipation and decoherence. Finally we discuss synchronization of a larger number of qubits.