arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1608.01664cond-mat.stat-mech
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弱可积破缺模型中的热化与光锥

Thermalization and light cones in a model with weak integrability breaking

Bruno Bertini, Fabian H. L. Essler, Stefan Groha, Neil J. Robinson

摘要:

利用运动方程方法研究了弱相互作用无自旋费米子晶格模型中的非平衡动力学。我们的模型提供了一个简单的设置来分析弱可积性破缺微扰对量子猝灭后时间演化的影响。我们建立的方法的准确性进行比较,在短期和中期的时间依赖的密度矩阵重整化群计算的结果。对于足够弱的可积性破缺相互作用,我们总是观察到预热化高原,在中间的时间尺度上,局部观测值放松到非热化值。在以后的时间里,一个向热行为的交叉开始。我们确定相关的时间尺度,这取决于初始状态,非相互作用理论的能带结构,和可积性破坏扰动的强度。我们的方法使我们能够在一定程度上详细分析相关性的传播,特别是我们模型中相关光锥的结构。我们发现,内部和外部的光锥是由一个中间区域,其时间宽度似乎规模与普遍的幂律$t^{1/3}$。

英文摘要:

We employ equation of motion techniques to study the non-equilibrium dynamics in a lattice model of weakly interacting spinless fermions. Our model provides a simple setting for analyzing the effects of weak integrability breaking perturbations on the time evolution after a quantum quench. We establish the accuracy of the method by comparing results at short and intermediate times to time-dependent density matrix renormalization group computations. For sufficiently weak integrability-breaking interactions we always observe prethermalization plateaux, where local observables relax to non-thermal values at intermediate time scales. At later times a crossover towards thermal behaviour sets in. We determine the associated time scale, which depends on the initial state, the band structure of the non-interacting theory, and the strength of the integrability breaking perturbation. Our method allows us to analyze in some detail the spreading of correlations and in particular the structure of the associated light cones in our model. We find that the interior and exterior of the light cone are separated by an intermediate region, the temporal width of which appears to scale with a universal power-law $t^{1/3}$.

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