arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0911.4015cond-mat.stat-mechcond-mat.soft
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Kovacs效应:主方程分析

The Kovacs effect: a master equation analysis

A. Prados, J. J. Brey

摘要:

Kovacs或交叉效应是玻璃和其他复杂的缓慢弛豫系统所表现出的特殊行为之一。粗略地说,它包括从非平衡态开始,在恒温下演化的系统的宏观性质向其平衡值的非单调松弛。在这里,这种效果是一般系统的动态描述的主方程。为了进行详细的分析,考虑了线性响应理论所适用的小扰动的极限。结果表明,在非常一般的条件下,所观察到的实验特征的科瓦奇效应恢复。结果是一个非常简单的模型,一个两能级系统的动力学无序。一个明确的解析表达式,其非单调松弛函数,显示了共振的行为时,对温度的依赖性进行了调查。

英文摘要:

The Kovacs or crossover effect is one of the peculiar behaviours exhibited by glasses and other complex, slowly relaxing systems. Roughly it consists in the non-monotonic relaxation to its equilibrium value of a macroscopic property of a system evolving at constant temperature, when starting from a non-equilibrium state. Here, this effect is investigated for general systems whose dynamics is described by a master equation. To carry out a detailed analysis, the limit of small perturbations in which linear response theory applies is considered. It is shown that, under very general conditions, the observed experimental features of the Kovacs effect are recovered. The results are particularized for a very simple model, a two-level system with dynamical disorder. An explicit analytical expression for its non-monotonic relaxation function is obtained, showing a resonant-like behaviour when the dependence on the temperature is investigated.

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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