A random unitary circuit model for black hole evaporation
A random unitary circuit model for black hole evaporation
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DOI：
10.1007/jhep04(2020)063
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发表时间：
2020-02
影响因子：
5.4
通讯作者：
L. Piroli;Christoph Sünderhauf;X. Qi
中科院分区：
文献类型：
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作者：
L. Piroli;Christoph Sünderhauf;X. Qi
受黑洞蒸发的Hayden-Preskill协议的启发，我们考虑了耦合到外部环境的量子多体量子系统的动力学，其中时间演化是由某些2-局域随机幺正回路的连续极限驱动的.我们研究了两种情况下，酉选择与不保守的U（1）电荷，并专注于两个方面的动力学。首先，我们分析和数值研究了系统纠缠熵的增长，表明两个不同的时间尺度出现：一个是内在的内部动力学（混乱时间），而另一个依赖于系统-环境耦合。在存在U（1）守恒荷的情况下，纠缠度随时间的变化遵循Page型行为：在“蒸发”的中间阶段纠缠度开始减小，然后单调减小.其次，我们研究了从环境qudits的测量中检索最初注入系统中的信息所需的时间。基于显式的数值计算，我们描述了这样的时间，当检索器控制初始配置或没有，显示出不同的尺度出现在两种情况下。
Inspired by the Hayden-Preskill protocol for black hole evaporation, we consider the dynamics of a quantum many-body qudit system coupled to an external environment, where the time evolution is driven by the continuous limit of certain 2-local random unitary circuits. We study both cases where the unitaries are chosen with and without a conserved U (1) charge and focus on two aspects of the dynamics. First, we study analytically and numerically the growth of the entanglement entropy of the system, showing that two different time scales appear: one is intrinsic to the internal dynamics (the scrambling time), while the other depends on the system-environment coupling. In the presence of a U (1) conserved charge, we show that the entanglement follows a Page-like behavior in time: it begins to decrease in the middle stage of the “evaporation”, and decreases monotonically afterwards. Second, we study the time needed to retrieve information initially injected in the system from measurements on the environment qudits. Based on explicit numerical computations, we characterize such time both when the retriever has control over the initial configuration or not, showing that different scales appear in the two cases.