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arXiv 1002.2842cond-mat.stat-mechhep-thquant-ph
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可积量子自旋链中猝灭后的长时间动力学:定域与非定域算符和有效热行为

Long time dynamics following a quench in an integrable quantum spin chain: local versus non-local operators and effective thermal behavior

Davide Rossini, Sei Suzuki, Giuseppe Mussardo, Giuseppe E. Santoro, Alessandro Silva

摘要:

我们研究了横向场强度零温猝灭后量子伊辛链的动力学。通过对两点自旋关联函数的研究,我们发现序参量的量子化子具有有效的渐近热行为,即,它们以由平衡定律规定的相位相干率和相关长度指数衰减到零,有效温度由初始状态的能量设定。相反,横向磁化强度的两点关联函数或扭结密度算符的两点关联函数按幂律衰减,不表现出热行为。我们认为,不同的行为是链接到相应的运营商的局部性相对于准粒子的模型:非本地运营商,如序参量,表现热,而本地的没有。我们研究的两点扩散子的功能是一个后果的可积性的模型,通过分析其鲁棒性方面的一个足够强的可积性破缺项。

英文摘要:

We study the dynamics of the quantum Ising chain following a zero-temperature quench of the transverse field strength. Focusing on the behavior of two-point spin correlation functions, we show that the correlators of the order parameter display an effective asymptotic thermal behavior, i.e., they decay exponentially to zero, with a phase coherence rate and a correlation length dictated by the equilibrium law with an effective temperature set by the energy of the initial state. On the contrary, the two-point correlation functions of the transverse magnetization or the density-of-kinks operator decay as a power-law and do not exhibit thermal behavior. We argue that the different behavior is linked to the locality of the corresponding operator with respect to the quasi-particles of the model: non-local operators, such as the order parameter, behave thermally, while local ones do not. We study which features of the two-point correlators are a consequence of the integrability of the model by analizing their robustness with respect to a sufficiently strong integrability-breaking term.

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