Density Distribution of Bose Condensed Gas in a Three—Dimensional Optical Lattice

For the Bose-condensed gas in a magnetic trap and three-dimensional optical lattice,the non-unifrom distribution of the atoms in different lattice sited in investigated and a propagatro method is used to study the evolution of the interference pattern after the combined potentials are switched off.The analytical result of the wavefunction at any time t is given and especially the motion of the side peaks is described by a simple analytical expression.     

弱相互作用玻色气体的涡旋解

在柱坐标系中,求出了绝对零度情况下近理想玻色气体涡旋态的波函数和能量的近似解析形式．     

玻色气体的磁性

物质磁性一直是凝聚态物理研究的重要课题.以往对磁性的探索主要是以费米子（局域或巡游的电子）为研究对象.由于传统的玻色系统液氦没有自旋,不表现磁性,玻色系统的磁性很少被关注.碱金属原子气体玻色-爱因斯坦凝聚的实现,在开辟了冷原子物理研究领域的同时,也打开了研究玻色系统磁性的大门.这是因为碱金属原子通常具有超精细结构,是旋量玻色气体,能够展示磁性.文章通过对比费米气体的相关结果,介绍了旋量玻色气体磁性的研究概况和最新进展,特别是铁磁性玻色气体的磁性相变以及在低温下铁磁性凝聚体的动力学特征.     

玻色气体的磁性

物质磁性一直是凝聚态物理研究的重要课题.以往对磁性的探索主要是以费米子(局域或巡游的电子)为研究对象.由于传统的玻色系统液氦没有自旋,不表现磁性,玻色系统的磁性很少被关注.碱金属原子气体玻色-爱因斯坦凝聚的实现,在开辟了冷原子物理研究领域的同时,也打开了研究玻色系统磁性的大门.这是因为碱金属原子通常具有超精细结构,是旋量玻色气体,能够展示磁性.文章通过对比费米气体的相关结果,介绍了旋量玻色气体磁性的研究概况和最新进展,特别是铁磁性玻色气体的磁性相变以及在低温下铁磁性凝聚体的动力学特征.     

Ground-state properties of dilute one-dimensional Bose gas with three-body repulsion

We determined perturbatively the low-energy universal thermodynamics of dilute one-dimensional bosons with the three-body repulsive forces. The final results are presented for the limit of vanishing potential range in terms of three-particle scattering length. An analogue of Tan's energy theorem for considered system is derived in generic case without assuming weakness of the interparticle interaction. We also obtained an exact identity relating the three-body contact to the energy density.     

Magnetic properties of two-dimensional charged spin-1 Bose gases

Within the mean-field theory, we investigate the magnetic properties of a charged spin-1 Bose gas in two dimensions. In this system the diamagnetism competes with paramagnetism, where the Landé factor g   is introduced to describe the strength of the paramagnetic effect. The system presents a crossover from diamagnetism to paramagnetism with the increasing of the Landé factor. _gc$g_c$ denotes the critical value of the Landé factor. We get the same value of _gc$g_c$ both in the low temperature and strong magnetic field limit. Our results also show that in very weak magnetic field no condensation happens in the two-dimensional charged spin-1 Bose gas.     

Analytical approach to relaxation dynamics of condensed Bose gases

The temporal evolution of a perturbation of the equilibrium distribution of a condensed Bose gas is investigated using the kinetic equation which describes collision between condensate and noncondensate atoms. The dynamics is studied in the low momentum limit where an analytical treatment is feasible. Explicit results are given for the behavior at large times in different temperature regimes.     

Thermodynamic properties of rotating trapped ideal Bose gases

Ultracold atomic gases can be spined up either by confining them in rotating frame, or by introducing “synthetic” magnetic field. In this paper, thermodynamics of rotating ideal Bose gases are investigated within truncated-summation approach which keeps to take into account the discrete nature of energy levels, rather than to approximate the summation over single-particle energy levels by an integral as it does in semi-classical approximation. Our results show that Bose gases in rotating frame exhibit much stronger dependence on rotation frequency than those in “synthetic” magnetic field. Consequently, BEC can be more easily suppressed in rotating frame than in “synthetic” magnetic field.     

On the Bose gas with local mean-field interaction

A Bose gas model is considered where the interaction term is proportional to the integral over the square of the local particle density. This model exhibits a phase transition with the same critical behavior as the usual mean-field (imperfect) Bose gas, but only generalized condensation may occur, due to boundary conditions.