Ultracold bosons with cavity-mediated long-range interactions: A local mean-field analysis of the phase diagram
Ultracold bosons with cavity-mediated long-range interactions: A local mean-field analysis of the phase diagram
复制标题
DOI：
10.1103/physreva.94.033607
复制
发表时间：
2016-06
影响因子：
2.9
通讯作者：
A. Niederle;G. Morigi;H. Rieger
中科院分区：
文献类型：
--
作者：
A. Niederle;G. Morigi;H. Rieger
当光晶格中的超冷玻色子原子被放入单模腔中并被激光抽运时，可以自组织成各种结构相和量子相。空腔光力学效应在与光学晶格排列相竞争的空腔模波长处诱导原子密度调制。同时，通过粒子跳跃的短程相互作用促进了超流体的有序，从而可以发生各种结构和量子相干相。我们利用扩展的Bose-Hubbard模型，结合局部平均场方法和超流体聚类分析，在二维上分析了新兴相图。当腔和外部晶格波长的比例相当时，电荷密度波和超固相的出现改变了莫特绝缘体-超流体跃迁，原子密度支持腔场的形成。对于不相称的比例，光机械力诱导玻色玻璃相和超玻璃相的形成，即非超流体相和超流体相，分别表现出准周期的密度调制，并表现出结构和超流体条纹的形成。这种结构的开始受到现场相互作用的限制，并且在分数密度下是有利的。对实验观测值进行了识别和讨论。
Ultracold bosonic atoms in optical lattices self-organize into a variety of structural and quantum phases when placed into a single-mode cavity and pumped by a laser. Cavity optomechanical effects induce an atom density modulation at the cavity-mode wavelength that competes with the optical lattice arrangement. Simultaneously short-range interactions via particle hopping promote superfluid order such that a variety of structural and quantum coherent phases can occur. We analyze the emerging phase diagram in two dimensions by means of an extended Bose-Hubbard model using a local mean-field approach combined with a superfluid cluster analysis. For commensurate ratios of the cavity and external lattice wavelengths, the Mott insulator-superfluid transition is modified by the appearance of charge density wave and supersolid phases, at which the atomic density supports the buildup of a cavity field. For incommensurate ratios, the optomechanical forces induce the formation of Bose-glass and superglass phases, namely, nonsuperfluid and superfluid phases, respectively, displaying quasiperiodic density modulations, which in addition can exhibit structural and superfluid stripe formation. The onset of such structures is constrained by the on-site interaction and is favorable at fractional densities. Experimental observables are identified and discussed.