Entanglement in a driven two-qubit system coupled to a common cavity
Phys. Rev. A 114, 033724 – Published 17 September, 2026
DOI: https://doi.org/10.1103/xvyj-hc3j
Abstract
A system, comprising a qubit pair coupled to a common cavity, is studied with the aim of establishing qubit entanglement. This study is a continuation of an earlier publication [Phys. Rev. A 111, 043705 (2025)], where a similar model was investigated for an initially vacuum cavity. In the present paper, a cavity with a 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 minimum value below which no maximally entangled qubit state is available. The threshold value is shown to depend critically on the initial number of photons present in the cavity. It is shown that a greater photon number prefers symmetric couplings for generating maximal entanglement. For a driven-dissipative case steady-state entanglement is shown to depend nonmonotonically on the qubit drive. For a moderate drive, steady-state entanglement decreases with decreasing coupling symmetry, leading to a regime of “no entanglement.” Interestingly, as the symmetry is further decreased, steady-state entanglement again becomes finite. The Intricate interplay of drive, dissipation, and coupling asymmetry is shown to be pivotal for steady-state entanglement generation.
