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arXiv 2402.12979cond-mat.stat-mech
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自由费米子的绝热规范势与可积性破缺

Adiabatic gauge potential and integrability breaking with free fermions

Balázs Pozsgay, Rustem Sharipov, Anastasiia Tiutiakina, István Vona

AI总结:

本文研究自由费米自旋链中 AGP 范数与可积性破缺的关系,证明局域费米子扰动即使强烈破坏可积性,AGP 范数仍始终多项式增长,并发现新的弱可积性破缺算符。

摘要:

我们重新考察了自由费米量子自旋链中的可积性破缺问题。我们研究了所谓的绝热规范势(AGP),它最近被提出作为量子混沌的精确探针。我们还研究了所谓的弱可积性破缺,这种情形发生在扰动的动力学效应在扰动参数的领头阶不出现时。文献中近期的一项论断声称,可积性破缺通常应导致 AGP 范数相对于体积呈指数增长。然而,随后人们发现弱可积性破缺是一个反例,会导致多项式增长与指数增长之间的渡越。在此我们表明,在自由费米系统中,如果扰动相对于费米子是局域的,那么即使该扰动强烈破坏可积性,AGP 范数也始终呈多项式增长。作为计算的副产品,我们还发现,在自由费米自旋链中存在一些会弱破坏可积性的算符,但它们与已知的长程形变无关。

英文摘要:

We revisit the problem of integrability breaking in free fermionic quantum spin chains. We investigate the so-called adiabatic gauge potential (AGP), which was recently proposed as an accurate probe of quantum chaos. We also study the so-called weak integrability breaking, which occurs if the dynamical effects of the perturbation do not appear at leading order in the perturbing parameter. A recent statement in the literature claimed that integrability breaking should generally lead to an exponential growth of the AGP norm with respect to the volume. However, afterwards it was found that weak integrability breaking is a counter-example, leading to a cross-over between polynomial and exponential growth. Here we show that in free fermionic systems the AGP norm always grows polynomially, if the perturbation is local with respect to the fermions, even if the perturbation strongly breaks integrability. As a by-product of our computations we also find, that in free fermionic spin chains there are operators which weakly break integrability, but which are not associated with known long range deformations.

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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