Delocalization and superfluidity of ultracold bosonic atoms in a ring lattice
Delocalization and superfluidity of ultracold bosonic atoms in a ring lattice
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环晶格中超冷玻色子原子的离域和超流动性
DOI：
10.1088/0953-4075/46/20/205303
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
A. T. Piza
中科院分区：
文献类型：
--
作者：
Fernanda R. Pinheiro;Fernanda R. Pinheiro;Fernanda R. Pinheiro;A. T. Piza
通过在截断多体空间中进行精确对角化，研究了具有周期准一维环面晶格势的旋转小系统中玻色子原子的性质。多体哈密顿量的展开式考虑了第一波段布洛赫函数，并且不涉及对最近邻跳变的限制（紧约束近似）的假设。费雪等人（1989）的零温度相图的有限尺寸版本。得到了Rev. B 40 546570)，并讨论了与更大系统的结果有显著定量对应的结果。在双流体现象学的背景下，研究了与超流动性有关的基态性质。基本工具由实验室框架中与小旋转角速度相关的固有惯性组成，用于数值计算基态“超流体分数”。在采用几何结构的情况下，它们解析地与一体、均匀的螺线管电流相关联。一般来说，这些电流是相关的简化的单体密度的每个特征态的贡献的非相干叠加，以相应的职业数作为权重。因此，只有当一个本征态被所有玻色子占据时，才会发生完全相干。得到的超流体分数数值在对应于“莫特绝缘子到超流体”转变的参数区域内保持较小，只有当晶格完全平滑时才达到统一饱和。
Properties of bosonic atoms in small systems with a periodic quasi-one-dimensional circular toroidal lattice potential subjected to rotation are examined by performing the exact diagonalization in a truncated many-body space. The expansion of the many-body Hamiltonian is considered in terms of the first-band Bloch functions, and no assumption regarding restriction to nearest neighbour hopping (tight-binding approximation) is involved. A finite size version of the zero temperature phase diagrams of Fisher et al (1989 Phys. Rev. B 40 546570) is obtained and the results, in remarkable quantitative correspondence with the results available for larger systems, discussed. Ground-state properties relating to superfluidity are examined in the context of two-fluid phenomenology. The basic tool, consisting of the intrinsic inertia associated with small rotation angular velocities in the lab frame, is used to obtain the ground state ‘superfluid fractions’ numerically. They are analytically associated with one-body, uniform solenoidal currents in the case of the adopted geometry. These currents are in general incoherent superpositions of contributions from each eigenstates of the associated reduced one-body densities, with the corresponding occupation numbers as weights. Full coherence occurs therefore only when only one eigenstate is occupied by all bosons. The obtained numerical values for the superfluid fractions remain small throughout the parameter region corresponding to the ‘Mott insulator to superfluid’ transition, and saturate at unity only as the lattice is completely smoothed out.
影响因子：
8.6
作者：
Cooper, Nigel R.;Hadzibabic, Zoran
通讯作者：
Hadzibabic, Zoran