Quantum thermalization through entanglement in an isolated many-body system
Quantum thermalization through entanglement in an isolated many-body system
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DOI：
10.1126/science.aaf6725
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发表时间：
2016-08-19
期刊：
影响因子：
56.9
通讯作者：
Greiner, Markus
中科院分区：
文献类型：
--
作者：
Kaufman, Adam M.;Tai, M. Eric;Greiner, Markus
统计力学依赖于系统在热平衡时的最大熵。然而，在纯态下初始化的孤立量子多体系统在薛定谔演化过程中仍然是纯的，在这个意义上它具有静态的零熵。我们在实验上研究了统计力学在量子态中的出现，并观察到量子纠缠在促进这种出现中的基本作用。对演化中的量子系统的显微镜观察表明，完整的量子态保持纯净，而热化作用发生在局部尺度上。我们直接测量了纠缠熵，它承担了热熵在热化过程中的作用。这种纠缠创造了局域熵，验证了统计物理对局域可观测性的使用。我们的测量结果与本征态热化假设是一致的。
Statistical mechanics relies on the maximization of entropy in a system at thermal equilibrium. However, an isolated quantum many-body system initialized in a pure state remains pure during Schrodinger evolution, and in this sense it has static, zero entropy. We experimentally studied the emergence of statistical mechanics in a quantum state and observed the fundamental role of quantum entanglement in facilitating this emergence. Microscopy of an evolving quantum system indicates that the full quantum state remains pure, whereas thermalization occurs on a local scale. We directly measured entanglement entropy, which assumes the role of the thermal entropy in thermalization. The entanglement creates local entropy that validates the use of statistical physics for local observables. Our measurements are consistent with the eigenstate thermalization hypothesis.