Speed of quantum information spreading in chaotic systems
Speed of quantum information spreading in chaotic systems
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DOI：
10.1103/physrevb.102.045114
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发表时间：
2019-08
影响因子：
3.7
通讯作者：
Josiah D. Couch;Stefan Eccles;P. Nguyen;Brian Swingle;Shenglong Xu
中科院分区：
文献类型：
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作者：
Josiah D. Couch;Stefan Eccles;P. Nguyen;Brian Swingle;Shenglong Xu
提出了混沌量子多体系统中量子信息传播的一般理论。在这样的系统中，一般的期望是量子信息不会以局域形式传播；相反，它倾向于分散并混乱成一种无法进行本地测量的形式。为了描述这种扩散，我们通过淬火型实验定义了一个信息速度，并推导出其作为初始状态纠缠密度函数的一般公式。当纠缠密度从0到1变化时，信息速度从纠缠速度到蝴蝶速度变化。我们验证了该公式既适用于量子混沌自旋链，也适用于具有AdS/CFT引力对偶的场论。对于第二种情况，我们详细研究了双面Vaidya-AdS-Reissner-Nordstrom黑膜的纠缠动力学。我们还表明，通过适当的解码过程，量子信息可以被解释为以信息速度移动，并且，在AdS/CFT的情况下，我们表明局部可检测的信号在可穿越虫洞设置的空间局部变体中以信息速度传播。
We present a general theory of quantum information propagation in chaotic quantum many-body systems. The generic expectation in such systems is that quantum information does not propagate in localized form; instead, it tends to spread out and scramble into a form that is inaccessible to local measurements. To characterize this spreading, we define an information speed via a quench-type experiment and derive a general formula for it as a function of the entanglement density of the initial state. As the entanglement density varies from zero to one, the information speed varies from the entanglement speed to the butterfly speed. We verify that the formula holds both for a quantum chaotic spin chain and in field theories with an AdS/CFT gravity dual. For the second case, we study in detail the dynamics of entanglement in two-sided Vaidya-AdS-Reissner-Nordstrom black branes. We also show that, with an appropriate decoding process, quantum information can be construed as moving at the information speed, and, in the case of AdS/CFT, we show that a locally detectable signal propagates at the information speed in a spatially local variant of the traversable wormhole setup.