Wang Jianhui, He Jizhou, Ma Yongli
Department of Physics, Nanchang University, Nanchang, China.
Phys Rev E Stat Nonlin Soft Matter Phys. 2011 May;83(5 Pt 1):051132. doi: 10.1103/PhysRevE.83.051132. Epub 2011 May 31.
Based on counting statistics and Bogoliubov theory, we present a recurrence relation for the microcanonical partition function for a weakly interacting Bose gas with a finite number of particles in a cubic box. According to this microcanonical partition function, we calculate numerically the distribution function, condensate fraction, and condensate fluctuations for a finite and isolated Bose-Einstein condensate. For ideal and weakly interacting Bose gases, we compare the condensate fluctuations with those in the canonical ensemble. The present approach yields an accurate account of the condensate fluctuations for temperatures close to the critical region. We emphasize that the interactions between excited atoms turn out to be important for moderate temperatures.
基于计数统计和博戈留波夫理论，我们给出了在立方盒中具有有限数量粒子的弱相互作用玻色气体的微正则配分函数的递推关系。根据这个微正则配分函数，我们数值计算了有限且孤立的玻色 - 爱因斯坦凝聚体的分布函数、凝聚分数和凝聚涨落。对于理想和弱相互作用玻色气体，我们将凝聚涨落与正则系综中的涨落进行了比较。本方法能准确描述接近临界区域温度下的凝聚涨落。我们强调，对于中等温度，激发原子之间的相互作用变得很重要。
