玻色-爱因斯坦凝聚均匀系统中集体激发的朗道阻尼

Landau Damping of Collective Excitation in Homogeneous Bose-Einstein Condensate

应用哈特里-福克-博戈留波夫(HFB)平均场理论研究玻色-爱因斯坦凝聚(BEC)均匀系统中集体激发的朗道阻尼。首先,不采用准粒子共振跃迁和集体激发能量两个条件近似进行严格推导,在参量变化较大的范围内给出朗道阻尼与温度的函数关系,重点讨论趋近绝对零度和相变临界温度两种极限情况,并引入误差函数分析不同能量的准粒子跃迁对阻尼的贡献。然后,采用上述两个近似进行推导,并利用误差函数计算结果分析两种近似的适用范围。

Landau damping of collective excitation in a homogeneous Bose-Einstein condensate(BEC)is studied by the Hartree-Fock-Bogoliubov(HFB)mean-field theory.The rigorous derivation is carried out without using the two approximations of quasi-particle resonance transition and collective excitation energy.The Landau damping as a function of temperature is given in a wide parameter range,and two limits of absolute zero and critical temperature of phase transition are highlighted.The contribution of quasi-particle transitions with different energies to damping is analyzed by the error function.In addition,the above two approximations are used for derivation,and the applicable range of the approximations is analyzed by the results of the error function.