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arXiv 2204.03088quant-phcond-mat.dis-nncond-mat.stat-mechhep-thmath-phmath.MP
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随机量子线路的有效场论

Effective field theory of random quantum circuits

Yunxiang Liao, Victor Galitski

摘要:

量子线路已经被广泛地用作模拟一般量子多体系统的平台。特别是,随机量子线路提供了一种手段来探测多体量子混沌和遍历性的普遍特征。一些这样的特性已经在有噪声的中尺度量子(NISQ)器件中得到了实验证明。在理论方面,随机量子线路的性质已经在个案基础上进行了研究,对于某些特定的系统,量子混沌的标志-通用维格纳-戴森能级统计-已经推导出来。本文发展了一大类随机量子线路的有效场论。该理论具有复制西格玛模型的形式,并且类似于无序系统中扩散的低能方法。该方法被用来显式地导出一个大家族的随机电路的通用随机矩阵行为。特别是,我们重新推导了Chan,De Luca和Chalker [Phys. Rev. X 8,041019(2018)]的砖砌电路模型的Wigner-Dyson谱统计,并在同一计算中表明其各种排列和高维推广保持了普遍的水平统计。最后,我们利用复制西格玛模型框架重新推导了紧群上矩阵元多项式关于Haar测度的积分计算方法Weingarten演算,该方法在量子线路的研究中有着广泛的应用.这里导出的有效场论提供了一种定量表征随机Floquet系统的量子动力学的方法(例如,计算算符和纠缠扩展),也是理解这些系统中量子混沌和热化背后的一般基本机制的途径。

英文摘要:

Quantum circuits have been widely used as a platform to simulate generic quantum many-body systems. In particular, random quantum circuits provide a means to probe universal features of many-body quantum chaos and ergodicity. Some such features have already been experimentally demonstrated in the noisy intermediate-scale quantum (NISQ) devices. On the theory side, properties of random quantum circuits have been studied on a case-by-case basis and for certain specific systems, a hallmark of quantum chaos - universal Wigner-Dyson level statistics - has been derived. This work develops an effective field theory for a large class of random quantum circuits. The theory has the form of a replica sigma model and is similar to the low-energy approach to diffusion in disordered systems. The method is used to explicitly derive universal random matrix behavior of a large family of random circuits. In particular, we rederive Wigner-Dyson spectral statistics of the brickwork circuit model by Chan, De Luca, and Chalker [Phys. Rev. X 8, 041019 (2018)] and show within the same calculation that its various permutations and higher-dimensional generalizations preserve the universal level statistics. Finally, we use the replica sigma model framework to rederive the Weingarten calculus, which is a method to evaluate integrals of polynomials of matrix elements with respect to the Haar measure over compact groups and has many applications in the studies of quantum circuits. The effective field theory, derived here, provides both a method to quantitatively characterize quantum dynamics of random Floquet systems (e.g., calculating operator and entanglement spreading) and also path to understanding the general fundamental mechanism behind quantum chaos and thermalization in these systems.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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