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arXiv 1003.1065cond-mat.stat-mech
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二次量的涨落与非线性响应函数

Fluctuations of two-time quantities and non-linear response functions

Federico Corberi, Eugenio Lippiello, Alessandro Sarracino, Marco Zannetti

摘要:

我们研究的自相关和autoresponse函数的波动,特别是,他们的方差和协方差。在文章的第一个一般部分,我们证明了响应函数的方差与复合算子的二阶磁化率的等价性,并且我们推导出了一个超越线性阶的平衡涨落耗散定理,将其与其他方差联系起来。在本文的第二部分中,我们应用的形式主义的研究非无序铁磁体,在平衡或在粗化动力学的临界或亚临界淬火。我们数值表明,方差和非线性磁化率服从缩放相对于在平衡的相干长度$ξ$,并相对于淬火后的增长长度$L(t)$,类似于已知的自相关和自响应函数。

英文摘要:

We study the fluctuations of the autocorrelation and autoresponse functions and, in particular, their variances and co-variance. In a first general part of the Article, we show the equivalence of the variance of the response function with the second-order susceptibility of a composite operator, and we derive an equilibrium fluctuation-dissipation theorem beyond-linear order relating it to the other variances. In a second part of the paper we apply the formalism to the study to non-disordered ferromagnets, in equilibrium or in the coarsening kinetics following a critical or sub-critical quench. We show numerically that the variances and the non-linear susceptibility obey scaling with respect to the coherence length $ξ$ in equilibrium, and with respect to the growing length $L(t)$ after a quench, similarly to what is known for the autocorrelation and the autoresponse functions.

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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