论文标题
在两个维度和三维中多体定位的数值证据
Numerical evidence for many-body localization in two and three dimensions
论文作者
论文摘要
疾病和相互作用会导致某些量子系统中统计力学的崩溃,这种现象称为多体定位(MBL)。 MBL的大部分现象学来自$ \ ell $ bit的存在,这是一组准局部和二进制的保守数量(即,仅具有$ \ pm 1 $ eigenvalues)。虽然已知MBL和$ \ ell $ - 位在一维系统中存在,但它们的存在大于一个是一个关键的开放问题。为了解决这个问题,我们开发了一种算法,可以通过自适应生成代表$ \ ell $ -bit的操作员的基础来找到任意维度的近似二进制$ \ ell $ bits。我们使用算法来研究四个模型:一,二维和三维无序的海森堡模型和二维无序的硬核硬质bose-Hubbard模型。对于研究的所有四个模型,我们的算法都发现,在$ \ ell $ bit的分布中,尤其是尤其是混乱的优势范围的分布的高质量$ \ ell $ bits的高质量变化,这表明存在MBL的过渡。在一维的海森堡模型和二维的玻色 - 哈伯德模型中,这些过渡与这些模型中关键障碍强度的过去估计很好地估计了我们研究了其他二维和三维模型中MBL现象学的证据。除了在较高维度中找到MBL行为外,我们的算法还可用于探测各种几何和维度的MBL。
Disorder and interactions can lead to the breakdown of statistical mechanics in certain quantum systems, a phenomenon known as many-body localization (MBL). Much of the phenomenology of MBL emerges from the existence of $\ell$-bits, a set of conserved quantities that are quasilocal and binary (i.e., possess only $\pm 1$ eigenvalues). While MBL and $\ell$-bits are known to exist in one-dimensional systems, their existence in dimensions greater than one is a key open question. To tackle this question, we develop an algorithm that can find approximate binary $\ell$-bits in arbitrary dimensions by adaptively generating a basis of operators in which to represent the $\ell$-bit. We use the algorithm to study four models: the one-, two-, and three-dimensional disordered Heisenberg models and the two-dimensional disordered hard-core Bose-Hubbard model. For all four of the models studied, our algorithm finds high-quality $\ell$-bits at large disorder strength and rapid qualitative changes in the distributions of $\ell$-bits in particular ranges of disorder strengths, suggesting the existence of MBL transitions. These transitions in the one-dimensional Heisenberg model and two-dimensional Bose-Hubbard model coincide well with past estimates of the critical disorder strengths in these models which further validates the evidence of MBL phenomenology in the other two and three-dimensional models we examine. In addition to finding MBL behavior in higher dimensions, our algorithm can be used to probe MBL in various geometries and dimensionality.