Opt Express. 2023 Feb 27;31(5):8548-8560. doi: 10.1364/OE.480191.
In this paper, we study steady-state quantum entanglement and steering in an open Dicke model where cavity dissipation and individual atomic decoherence are taken into account. Specifically, we consider that each atom is coupled to independent dephasing and squeezed environments, which makes the widely-adopted Holstein-Primakoff approximation invalid. By discovering the features of quantum phase transition in the presence of the decohering environments, we mainly find that (i) in both normal and superradiant phases, the cavity dissipation and individual atomic decoherence can improve the entanglement and steering between the cavity field and atomic ensemble; (ii) the individual atomic spontaneous emission leads to the appearance of the steering between the cavity field and atomic ensemble but the steering in two directions cannot be simultaneously generated; (iii) the maximal achievable steering in normal phase is stronger than that in superradiant phase; (iv) the entanglement and steering between the cavity output field and the atomic ensemble are much stronger than that with the intracavity, and the steerings in two directions can be achieved even with the same parameters. Our findings reveal unique features of quantum correlations in the open Dicke model in the presence of individual atomic decoherence processes.
在本文中，我们研究了在考虑腔耗散和单个原子退相干的开放 Dicke 模型中的稳态量子纠缠和引导。具体来说，我们考虑每个原子与独立的去相位和压缩环境耦合，这使得广泛采用的 Holstein-Primakoff 近似无效。通过发现退相干环境中量子相变的特征，我们主要发现：（i）在正常相和超辐射相中，腔耗散和单个原子退相干都可以提高腔场和原子集合体之间的纠缠和引导；（ii）单个原子自发发射导致腔场和原子集合体之间的引导出现，但不能同时产生两个方向的引导；（iii）正常相中的最大可实现引导比超辐射相中的要强；（iv）腔输出场与原子集合体之间的纠缠和引导比腔内的要强得多，即使使用相同的参数也可以实现两个方向的引导。我们的研究结果揭示了在存在单个原子退相干过程的情况下，开放 Dicke 模型中量子相关性的独特特征。
