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arXiv 1801.09669hep-thcond-mat.str-el
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超最大混沌与不稳定性

Super-maximal chaos and instability

Swapnamay Mondal

AI总结:

本研究探讨了热多体量子系统 Lyapunov 指数上限的物理机制,提出超最大混沌导致不稳定性的假说,并通过 SYK 晶格模型验证了相变点处扩散系数等物理量的发散现象。

摘要:

近期有人猜想热多体量子系统的 Lyapunov 指数存在一个上限。在本研究中,我们试图从物理上理解是什么阻止了系统违反该界限。为此,我们提出——超最大混沌会导致不稳定性。我们的提议得到了 SYK 晶格模型中研究结果的支持,该模型具有一个可调参数,Lyapunov 谱依赖于该参数。在该参数的稳定区域内,除了非相干金属相之外,系统还表现出一种新颖的相,其中的输运既不由准粒子控制,也不由扩散控制。在相变点,扩散系数、蝴蝶速度和 Thouless 时间均发散。

英文摘要:

An upper bound on Lyapunov exponent of a thermal many body quantum system has been conjectured recently. In this work, we attempt to achieve a physical understanding of what prevents a system from violating this bound. To this end, we propose - super-maximal chaos leads to instability. Our proposal is supported by findings in a SYK lattice model, with a tuneable parameter, which the Lyapunov spectrum depends upon. In the stable regime of this parameter, along with incoherent metallic phase, the system exhibits another novel phase, where transport is controlled neither by quasi-particles nor by diffusion. At the phase transition, diffusion coefficient, butterfly velocity and Thouless time diverges.

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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