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arXiv 2005.14188cond-mat.stat-mechcond-mat.dis-nn
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非平衡多体量子系统中的自平均:分布的时间依赖性

Self-averaging in many-body quantum systems out of equilibrium: Time dependence of distributions

E. Jonathan Torres-Herrera, Isaías Vallejo-Fabila, Andrei J. Martínez-Mendoza, Lea F. Santos

摘要:

在一个无序系统中,当一个量的无序实现方差与其平均值的平方之比随着系统大小的增加而减小时,该量是自平均的。在这里,我们考虑一个混沌无序多体量子系统和搜索之间的关系的自平均行为和各种数量的无序实现,在不同的时间尺度上的分布的属性。指数分布,如发现的生存概率在很长一段时间,解释了它缺乏自平均,因为平均值和分散是相等的。高斯分布,但是,获得自平均和非自平均量。我们的研究还表明,人们可以根据另一个相关量的分布来得出关于一个量的自平均行为的结论。这种策略允许半分析的结果,从而规避了数值尺度分析的局限性,这是有限的系统大小。

英文摘要:

In a disordered system, a quantity is self-averaging when the ratio between its variance for disorder realizations and the square of its mean decreases as the system size increases. Here, we consider a chaotic disordered many-body quantum system and search for a relationship between self-averaging behavior and the properties of the distributions over disorder realizations of various quantities and at different timescales. An exponential distribution, as found for the survival probability at long times, explains its lack of self-averaging, since the mean and the dispersion are equal. Gaussian distributions, however, are obtained for both self-averaging and non-self-averaging quantities. Our studies show also that one can make conclusions about the self-averaging behavior of one quantity based on the distribution of another related quantity. This strategy allows for semianalytical results, and thus circumvents the limitations of numerical scaling analysis, which are restricted to few system sizes.

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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