论文标题

安德森(Anderson

Anderson localisation in two dimensions: insights from Localisation Landscape Theory, exact diagonalisation, and time-dependent simulations

论文作者

Shamailov, Sophie S., Brown, Dylan J., Haase, Thomas A., Hoogerland, Maarten D.

论文摘要

由冷原子系统中的实验进步的动机,我们使用并推进定位景观理论(LLT)来检查具有点状随机散射器的二维系统。首先,我们表明确切的本征不能有效地用于提取定位长度。然后,我们对已知LLT进行了全面的综述,并确认具有LLT有效潜力的哈密顿量具有与物理潜力非常相似的低能量本征态。接下来,我们使用LLT来计算非常低能,最大局部特征状态的定位长度,并测试我们的方法,以确切的对角度化。此外,我们提出了一个最佳检测Anderson定位的传输实验,并演示了人们如何提取与(通常小于)定位长度相关的长度尺度。此外,我们研究了从一个维度到二维的尺寸交叉,为既定趋势提供了新的解释。直接的schrödinger时间演化测试了来自LLT的迁移率边缘的预测,并被认为是非物理的。此外,我们研究了扩展的波袋,以发现这些波袋可以在传输实验中检测和量化安德森本地化有用,唯一的缺点是无法解决定位长度的能量依赖性。然后,我们利用LLT来揭示安德森模型之间的连接,用于离散无序的晶格和连续的二维无序系统,该系统提供了强大的新见解。从这里开始,我们证明可以通过与有序电势中的动力学与所有其他属性不变的动力学进行比较来区分其他效果。最后,我们彻底研究了与当前实验有关的加速度和排斥性颗粒间相互作用的影响。

Motivated by experimental progress in cold atomic systems, we use and advance Localisation Landscape Theory (LLT), to examine two-dimensional systems with point-like random scatterers. We begin by showing that exact eigenstates cannot be efficiently used to extract the localisation length. We then provide a comprehensive review of known LLT, and confirm that the Hamiltonian with the effective potential of LLT has very similar low energy eigenstates to that with the physical potential. Next, we use LLT to compute the localisation length for very low-energy, maximally localised eigenstates and test our method against exact diagonalisation. Furthermore, we propose a transmission experiment that optimally detects Anderson localisation, and demonstrate how one may extract a length scale which is correlated with (and in general smaller than) the localisation length. In addition, we study the dimensional crossover from one to two dimensions, providing a new explanation to the established trends. The prediction of a mobility edge coming from LLT is tested by direct Schrödinger time evolution and is found to be unphysical. Moreover, we investigate expanding wavepackets, to find that these can be useful in detecting and quantifying Anderson localisation in a transmission experiment, with the only disadvantage being the inability to resolve the energy dependence of the localisation length. Then, we utilise LLT to uncover a connection between the Anderson model for discrete disordered lattices and continuous two-dimensional disordered systems, which provides powerful new insights. From here, we demonstrate that localisation can be distinguished from other effects by a comparison to dynamics in an ordered potential with all other properties unchanged. Finally, we thoroughly investigate the effect of acceleration and repulsive interparticle interactions, as relevant for current experiments.

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