Lin Fei, Maier T A, Scarola V W
Department of Physics, Virginia Tech, Blacksburg, Virginia, 24061, USA.
Computational Science and Engineering Division and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA.
Sci Rep. 2017 Oct 6;7(1):12752. doi: 10.1038/s41598-017-13040-9.
The extended Bose-Hubbard model captures the essential properties of a wide variety of physical systems including ultracold atoms and molecules in optical lattices, Josephson junction arrays, and certain narrow band superconductors. It exhibits a rich phase diagram including a supersolid phase where a lattice solid coexists with a superfluid. We use quantum Monte Carlo to study the supersolid part of the phase diagram of the extended Bose-Hubbard model on the simple cubic lattice. We add disorder to the extended Bose-Hubbard model and find that the maximum critical temperature for the supersolid phase tends to be suppressed by disorder. But we also find a narrow parameter window in which the supersolid critical temperature is enhanced by disorder. Our results show that supersolids survive a moderate amount of spatial disorder and thermal fluctuations in the simple cubic lattice.
扩展的玻色-哈伯德模型捕捉了多种物理系统的基本特性，包括光学晶格中的超冷原子和分子、约瑟夫森结阵列以及某些窄带超导体。它展现出一个丰富的相图，其中包括一个晶格固体与超流体共存的超固体相。我们使用量子蒙特卡罗方法来研究简单立方晶格上扩展玻色-哈伯德模型相图的超固体部分。我们在扩展玻色-哈伯德模型中加入无序，发现超固体相的最大临界温度往往会被无序抑制。但我们也发现了一个狭窄的参数窗口，其中超固体临界温度会因无序而增强。我们的结果表明，超固体在简单立方晶格中能经受适度的空间无序和热涨落。
