Slow dynamics in a two-dimensional Anderson-Hubbard model
Slow dynamics in a two-dimensional Anderson-Hubbard model
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DOI：
10.1209/0295-5075/113/46001
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发表时间：
2016-02-01
期刊：
影响因子：
1.8
通讯作者：
Reichman, David R.
中科院分区：
文献类型：
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作者：
Bar Lev, Yevgeny;Reichman, David R.
我们使用二阶近似中的非平衡自洽微扰理论研究二维 Anderson-Hubbard 模型的实时动力学。与在小簇上执行的精确对角化相比，我们证明，对于强无序，该技术在所有可用时间尺度上接近精确结果，而对于中度无序，在多体定位转换附近，它可以产生高达非平凡时间的定量准确结果。我们的方法允许处理任何数值精确方法无法访问的系统尺寸，并完全消除所考虑时间的有限尺寸效应。我们表明，对于足够强的无序，系统变得非遍历，而对于中等无序强度和所有可访问的时间尺度，系统中的传输是严格亚扩散的。我们认为这些结果与简单的渗流图不兼容，但与启发式随机电阻网络模型一致，在该模型中，可以长时间观察到子扩散，直到发生扩散交叉。二维相互作用和无序系统中慢速有限时间动力学的预测可以在未来的冷原子实验中直接验证。版权所有 (C) EPLA，2016
We study the real-time dynamics of a two-dimensional Anderson-Hubbard model using nonequilibrium self-consistent perturbation theory within the second-Born approximation. When compared with exact diagonalization performed on small clusters, we demonstrate that for strong disorder this technique approaches the exact result on all available timescales, while for intermediate disorder, in the vicinity of the many-body localization transition, it produces quantitatively accurate results up to nontrivial times. Our method allows for the treatment of system sizes inaccessible by any numerically exact method and for the complete elimination of finite-size effects for the times considered. We show that for a sufficiently strong disorder the system becomes nonergodic, while for intermediate disorder strengths and for all accessible timescales transport in the system is strictly subdiffusive. We argue that these results are incompatible with a simple percolation picture, but are consistent with the heuristic random resistor network model where subdiffusion may be observed for long times until a crossover to diffusion occurs. The prediction of slow finite-time dynamics in a two-dimensional interacting and disordered system can be directly verified in future cold-atoms experiments. Copyright (C) EPLA, 2016