论文标题
在波动操作员扩展方法中无序的二维玻色 - 哈伯德模型中定位过渡的有限尺寸缩放分析
Finite-size scaling analysis of localization transitions in the disordered two-dimensional Bose-Hubbard model within the fluctuation operator expansion method
论文作者
论文摘要
在非全能填充时，无序的Bose-Hubbard模型承认，在弱障碍时承认了Bose-Glass过渡的超氟。该系统的特性较低，在强障碍和与激发态相对应的能量密度方面的特性。在这项工作中，我们研究了基态的玻色玻璃跃迁和相关的有限能量定位过渡，即准粒子光谱的迁移率边缘，这是一种与局部准粒子激发延伸的关键能量。为了研究这些波动操作员的扩展。准粒子激发，相应波函数的分形维度和衰减的水平间距统计与多体迁移率边缘一致。最低间隙的有限尺寸缩放比例对超丝对玻色玻璃过渡的平均场预测进行了校正。在其附近，我们讨论了基态的光谱特性，以动态结构因子和光谱函数，在迁移率边缘上方和下方显示出不同的行为。
The disordered Bose-Hubbard model in two dimensions at non-integer filling admits a superfluid to Bose-glass transition at weak disorder. Less understood are the properties of this system at strong disorder and energy densities corresponding to excited states. In this work we study the Bose-glass transition of the ground state and the related finite energy localization transition, the mobility edge of the quasiparticle spectrum, a critical energy separating extended from localized quasiparticle excitations. To study these the fluctuation operator expansion is used. The level spacing statistics of the quasiparticle excitations, the fractal dimension and decay of the corresponding wave functions are consistent with a many-body mobility edge. The finite-size scaling of the lowest gaps yields a correction to the mean-field prediction of the superfluid to Bose-glass transition. In its vicinity we discuss spectral properties of the ground state in terms of the dynamic structure factor and the spectral function which also shows distinct behavior above and below the mobility edge.
