White M, Pasienski M, McKay D, Zhou S Q, Ceperley D, Demarco B
Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
Phys Rev Lett. 2009 Feb 6;102(5):055301. doi: 10.1103/PhysRevLett.102.055301. Epub 2009 Feb 5.
We experimentally probe the properties of the disordered Bose-Hubbard model using an atomic Bose-Einstein condensate trapped in a 3D disordered optical lattice. Controllable disorder is introduced using a fine-grained optical speckle field with features comparable in size to the lattice spacing along every lattice direction. A precision measurement of the disordering potential is used to compute the single-particle parameters of the system. To constrain theories of the disordered Bose Hubbard model, we have measured the change in condensate fraction as a function of disorder strength for several different ratios of tunneling to interaction energy. We observe disorder-induced, reversible suppression of condensate fraction for superfluid and coexisting superfluid-Mott-insulator phases.
我们使用被困在三维无序光学晶格中的原子玻色-爱因斯坦凝聚体，通过实验探究无序玻色-哈伯德模型的性质。利用细粒度光学散斑场引入可控无序，其特征尺寸在每个晶格方向上与晶格间距相当。对无序势进行精确测量以计算系统的单粒子参数。为了限制无序玻色-哈伯德模型的理论，我们测量了在几种不同隧穿与相互作用能比值下，凝聚分数随无序强度的变化。我们观察到，对于超流相以及共存的超流-莫特绝缘相，无序会导致凝聚分数出现无序诱导的可逆抑制。
