Kolovsky A R
Kirensky Institute of Physics and Siberian Federal University, 660036 Krasnoyarsk, Russia.
Phys Rev Lett. 2008 Nov 7;101(19):190602. doi: 10.1103/PhysRevLett.101.190602. Epub 2008 Nov 6.
This Letter studies the dynamics of a quantum particle in 2D lattices with on-site disorder in the presence of a static field. It is shown that the particle is localized along the field direction, while in the orthogonal direction to the field it shows diffusive dynamics for algebraically large times. For weak disorder an analytical expression for the diffusion coefficient is obtained by mapping the problem to a band random matrix. This expression is confirmed by numerical simulations of the particle's dynamics, which also indicate the existence of a universal equation for the diffusion coefficient, valid for an arbitrary disorder strength.
本信函研究了在存在静态场的情况下，二维晶格中具有在位无序的量子粒子的动力学。结果表明，粒子沿场方向局域化，而在与场正交的方向上，在代数意义上的长时间内表现出扩散动力学。对于弱无序，通过将问题映射到带随机矩阵，得到了扩散系数的解析表达式。粒子动力学的数值模拟证实了该表达式，同时也表明存在一个适用于任意无序强度的扩散系数通用方程。
