赝自旋1/2玻色气体中的相分离  

Phase Separation in a Pseudospin-half Bose Gas

作　　者：高炳杰 贺丽[2] GAO Bingjie;HE Li(Institute of Theoretical Physics,Shanxi University,Taiyuan 030006,China;College of Physics and Electronic Engineering,Shanxi University,Taiyuan 030006,China)

机构地区：[1]山西大学理论物理研究所,山西太原030006 [2]山西大学物理电子工程学院,山西太原030006

出　　处：《山西大学学报（自然科学版）》2024年第5期1015-1020,共6页Journal of Shanxi University(Natural Science Edition)

基　　金：国家自然科学基金(12104275;12174230)。

摘　　要：内态间的量子相干性对于旋量多体系统的宏观物性具有重要影响。本文运用平均场方法研究了赝自旋1/2玻色气体在Rabi耦合强度趋于零情形的基态相图。当同自旋原子具有非对称的排斥相互作用时,体系会在适当的失谐参数下发生两种自旋极化相反的饱和铁磁凝聚体的相分离。根据热力学的相平衡条件,确定了相分离态的密度范围。在转变区间,压强随体积的变化曲线呈现出类似于经典气液相变的平台特征。在顺磁相与相分离态的边界,等温压缩率趋于发散。我们讨论了这种相分离与非相干玻色混合气体中不混溶现象的区别。本文得到的结果为进一步研究旋量凝聚体在有限Rabi耦合强度下的基态性质提供了基础。The quantum coherence between the internal states has a significant impact on physical properties of a spinor many-body system.Using the mean-field theory,this work studies the ground state phase diagram of a pseudospin-half Bose gas with vanishing small Rabi coupling strength.When the intra-spin repulsive interactions are in an asymmetric form,the phase separation of two saturated ferromagnetic condensate with opposite spin-polarization occurs under the appropriate detuning parameters.The density interval for the phase-separated state is determined from the thermodynamic balance conditions.In the transition region,the pressure-volume curve shows a characteristic plateau,similar to a classic liquid-gas transition.At the phase boundary between the paramagnetic state and phase-separated state,the isothermal compressibility diverges.The contrast of such phase-separation with the immiscible phenomenon in the incoherent Bose mixture is discussed.The results obtained in this paper provide a basis for the further study of the ground state properties of a spinor condensate with finite Rabi coupling strength.

关 键 词：玻色-爱因斯坦凝聚体 旋量玻色气体 相分离 相变 

分 类 号：O51[理学—低温物理]