论文标题

被监视的量子电路中的超快纠缠动态

Ultrafast Entanglement Dynamics in Monitored Quantum Circuits

论文作者

Sang, Shengqi, Li, Zhi, Hsieh, Timothy H., Yoshida, Beni

论文摘要

投影测量是量子力学的基本操作,可以引起看似非本地的影响。在这项工作中,我们通过研究弱监测的量子电路的非平衡动力学来分析多体系统中的这种效果,重点是纠缠产生和信息传播。我们发现,由于测量值,被监视电路中的纠缠动态确实比单一的纠缠动态“快”。具体来说,我们发现一对良好的区域可能会在时间尺度上纠缠$ \ ell^{2/3} $,在其远处$ \ ell $中的子线。对于克利福德(Clifford)监控电路的情况,这起源于不断发展的状态的超级稳定器发生器。此外,我们发现最初的本地信息可以以$ t^{3/2} $为单位传播。此外,通过将动力学视为动力编码过程,我们表明,超级焊接的长度量表与系统大小的sublinear相关。为了量化信息动力学,我们开发了一种形式主义,将概括性操作员传播到非单身动态,这是一个独立的利益。

Projective measurement, a basic operation in quantum mechanics, can induce seemingly nonlocal effects. In this work, we analyze such effects in many-body systems by studying the non-equilibrium dynamics of weakly monitored quantum circuits, focusing on entanglement generation and information spreading. We find that, due to measurements, the entanglement dynamics in monitored circuits is indeed "faster" than that of unitary ones in several ways. Specifically, we find that a pair of well-separated regions can become entangled in a time scale $\ell^{2/3}$, sub-linear in their distance $\ell$. For the case of Clifford monitored circuits, this originates from super-ballistically growing stabilizer generators of the evolving state. In addition, we find initially local information can spread super-ballistically as $t^{3/2}$. Furthermore, by viewing the dynamics as a dynamical encoding process, we show that the super-ballistic growing length scale relates to an encoding time that is sublinear in system size. To quantify the information dynamics, we develop a formalism generalizing operator spreading to non-unitary dynamics, which is of independent interest.

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