Dynamical mean-field theory for bosons
Dynamical mean-field theory for bosons
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DOI：
10.1088/1367-2630/13/7/075013
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发表时间：
2011-02
影响因子：
3.3
通讯作者：
P. Anders;E. Gull;L. Pollet;M. Troyer;P. Werner
中科院分区：
文献类型：
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作者：
P. Anders;E. Gull;L. Pollet;M. Troyer;P. Werner
我们讨论了最近发展的玻色子动力学平均场理论（B-DMFT）的框架，该框架将玻色子晶格模型映射到玻色子杂质模型的自洽解上，并耦合到正常和凝聚玻色子的库。有效杂质作用量的推导有几种方式：（i）作为晶格问题的动能泛函的近似，（ii）使用腔方法和（iii）使用有效介质方法，该方法基于对自洽定义的凝聚体添加单圈校正。为了解决杂质的问题，我们使用连续时间蒙特卡罗算法的基础上采样的扰动展开的杂交函数和凝聚波函数。作为应用的形式主义，我们提出了有限温度的B-DMFT相图的玻色Hubbard模型的三维（3D）立方和2D正方形晶格，凝聚的序参数作为化学势的函数，临界指数的凝聚，弱相互作用的玻色气体制度的弱排斥和动能作为温度的函数的方法。
We discuss the recently developed bosonic dynamical mean-field theory (B-DMFT) framework, which maps a bosonic lattice model onto the self-consistent solution of a bosonic impurity model with coupling to a reservoir of normal and condensed bosons. The effective impurity action is derived in several ways: (i) as an approximation to the kinetic energy functional of the lattice problem, (ii) using a cavity approach and (iii) using an effective medium approach based on adding a one-loop correction to the self-consistently defined condensate. To solve the impurity problem, we use a continuous-time Monte Carlo algorithm based on the sampling of a perturbation expansion in the hybridization functions and the condensate wave function. As applications of the formalism, we present finite-temperature B-DMFT phase diagrams for the bosonic Hubbard model on a three-dimensional (3D) cubic and a 2D square lattice, the condensate order parameter as a function of chemical potential, critical exponents for the condensate, the approach to the weakly interacting Bose gas regime for weak repulsions and the kinetic energy as a function of temperature.