Entanglement prethermalization in an interaction quench between two harmonic oscillators
Entanglement prethermalization in an interaction quench between two harmonic oscillators
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两个谐振子之间相互作用猝灭中的纠缠预热化
DOI：
10.1103/physreve.95.022129
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
and Masahito Ueda
中科院分区：
文献类型：
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作者：
Tatsuhiko N. Ikeda;Takashi Mori;Eriko Kaminishi;and Masahito Ueda
纠缠预热化（Entanglement prethermalization， EP）是指复合系统的一种准平稳非平衡状态，在这种状态下，由于子系统之间的量子纠缠，单个子系统看起来是热的，但整个系统仍然是非热的。我们从理论上研究了两个相互作用玻色子被限制的一维谐波势相干分裂后的EP动力学。这个问题等价于两个谐振子之间的相互作用猝灭问题。我们证明，这个简单的模型捕捉到了EP的基本要素；也就是说，每个子系统松弛到一个近似的热平衡，而整个系统仍然纠缠。我们发现，如果我们考虑作用于两个子系统的非平凡的非局部守恒量，广义吉布斯系综精确地描述了整个系统。在对称性破缺扰动存在下，系统的弛豫动力学表现出准平稳的EP平台，最终达到热平衡。我们分析地表明，EP的寿命与扰动的大小成反比。
Entanglement prethermalization (EP) refers to a quasi-stationary nonequilibrium state of a composite system in which each individual subsystem looks thermal but the entire system remains nonthermal due to quantum entanglement between subsystems. We theoretically study the dynamics of EP following a coherent split of a one-dimensional harmonic potential in which two interacting bosons are confined. This problem is equivalent to that of an interaction quench between two harmonic oscillators. We show that this simple model captures the bare essentials of EP; that is, each subsystem relaxes to an approximate thermal equilibrium, whereas the total system remains entangled. We find that a generalized Gibbs ensemble exactly describes the total system if we take into account nonlocal conserved quantities that act nontrivially on both subsystems. In the presence of a symmetry-breaking perturbation, the relaxation dynamics of the system exhibits a quasi-stationary EP plateau and eventually reaches thermal equilibrium. We analytically show that the lifetime of EP is inversely proportional to the magnitude of the perturbation.