弱磁场中弱相互作用玻色气体的低温性质

Low-temperature properties of a weakly interacting Bose gas in weak magnetic field

运用局域密度近似方法以及非均匀系统中化学势不变原理的结论,研究低温条件下弱磁场中弱相互作用玻色气体的热力学性质,导出系统的基态占有率、凝聚区边界磁势、化学势、总能和热容量的解析式,分析磁场及粒子之间的相互作用对系统热力学性质的影响.研究结果表明,在保持相互排斥作用不变的情况下,变化的磁场对系统凝聚体积、总能、热容量的影响存在着各自的分界温度.相互排斥使系统的化学势均为正值且随温度下降而增加,使系统的总能抬高了一个平台并在很接近凝聚温度处有一极大值,使系统的热容量随温度的变化存在着反转点和极大值点,使总能和热容量在各自的极大值点开始随温度向凝聚温度逼近而急剧下降.

The low-temperature properties of a weakly interacting Bose gas in weak magnetic field were studied by using the conclusions of local-density approximation method and invariability principle of chemical potential in inhomogenous system. The analytical expressions of the ground-state fraction, boundary magnetic potential in condensation region, chemical potential, total energy and heat capacity were derived. The effects of magnetic field and interparticle interactions on properties of the system were discussed. It is shown that when repulsive interactions are kept constant, the effects of variational magnetic filed on condensation volume, total energy and heat capacity of the system have boundary temperature respectively. The repulsive interactions make the chemical potential of the system always positive and increase with the decreasing temperature, the total energy of the system is lifted a platform and a maximum is obtained near condensation temperature; the heat capacity of the system have the reversal point and the maximum point with the changing temperature ; and the total energy and heat capacity decrease rapidly from their own maximums with the temperature approaching to condensation temperature.