Thermalization and light cones in a model with weak integrability breaking
Thermalization and light cones in a model with weak integrability breaking
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DOI：
10.1103/physrevb.94.245117
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发表时间：
2016-12-09
影响因子：
3.7
通讯作者：
Robinson, Neil J.
中科院分区：
文献类型：
--
作者：
Bertini, Bruno;Essler, Fabian H. L.;Robinson, Neil J.
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，通过比较结果在短期和中期的时间依赖的密度矩阵重整化群计算。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平台，在中间的时间尺度上，局部观测值放松到非热的值。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，带结构的非相互作用理论，和强度的可积性破坏扰动。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。我们发现光锥的内部和外部被一个中间区域分开，其时间宽度似乎与普适幂律t（1/3）成比例。
We employ equation-of-motion techniques to study the nonequilibrium 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 plateaus, where local observables relax to nonthermal values at intermediate time scales. At later times a crossover towards thermal behavior sets in. We determine the associated time scale, which depends on the initial state, the band structure of the noninteracting 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).