Abstract We study the dynamics of two interacting two-level systems (qubits) having one of them isolated and the other coupled to a single mode electromagnetic field in a thermal state. The field plays the role of a small environment, in contrast to the usual approach of modelling an environment via a thermal reservoir with many degrees of freedom. We find the analytical solution of the proposed model, which allows us to investigate the consequences of the coupling to the small environment on characteristic quantum features of the two-qubit system. We study the time evolution of quantum entanglement and coherence, verifying the dependence on the relevant coupling constants as well as the influence of the effective temperature of the environment. Interestingly, we find that both sudden death and sudden birth of entanglement may occur in such a simple system. We also discuss a different partition, in which the isolated qubit is considered to be coupled to a composite environment, constituted by the other qubit plus the field mode.

中文翻译：

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由最小热环境引起的纠缠突然死亡

摘要 我们研究了两个相互作用的两级系统 (qubits) 的动力学，其中一个是隔离的，另一个是在热状态下耦合到单模电磁场。与通过具有许多自由度的热库对环境进行建模的通常方法相比，该场扮演着一个小环境的角色。我们找到了所提出模型的解析解，这使我们能够研究耦合到小环境对双量子位系统的特征量子特征的影响。我们研究了量子纠缠和相干性的时间演化，验证了对相关耦合常数的依赖性以及环境有效温度的影响。有趣的是，我们发现，在这样一个简单的系统中，可能会同时出现猝死和猝死的纠缠。我们还讨论了一个不同的分区，其中孤立的量子位被认为是耦合到一个复合环境，由另一个量子位加上场模式构成。