Entanglement in a driven two-qubit system coupled to common cavity

TL;DR

This paper investigates how a driven two-qubit system coupled to a common cavity can generate entanglement, considering cavity initial occupancy, asymmetric couplings, and the effects of drive and dissipation on steady-state entanglement.

Contribution

It extends previous work by analyzing finite initial cavity occupancy and asymmetric couplings, revealing thresholds and conditions for entanglement generation in driven-dissipative systems.

Findings

Threshold coupling ratio limits maximal entanglement in closed systems.

Steady-state entanglement depends non-monotonically on qubit drive.

Interplay of drive, dissipation, and asymmetry is crucial for entanglement.

Abstract

A system, comprised of a qubit pair coupled to a common cavity, is studied with the aim of establishing qubit entanglement. This study is the sequel of the paper Phys. Rev. A 111, 043705 (2025), where similar model was investigated for an initially vacuum cavity. In the present manuscript the cavity with finite initial occupancy is considered and the effect of asymmetric qubit cavity couplings is investigated. For a closed system scenario, the ratio of the qubit-cavity couplings shows a threshold beyond which no maximally-entangled qubit state is available. The threshold value is shown to depend on the excitation level of the cavity. For a driven-dissipative case steady state entanglement is shown to depend non-monotonically on the qubit drive. Intricate interplay of drive, dissipation, and coupling asymmetry is shown to be pivotal for steady-state entanglement generation.