非凝聚态粒子对超流临界速度实验值的影响

Effects of uncompensated particles on the experimental values of superfluity's critical velocity

超流关键的物理量就是临界速度,MIT(麻省理工学院)实验组用激光来回扫描凝聚体的方法测出BEC超流体的临界速度,但是与理论值相比小得多.考虑到非凝聚态粒子的影响,发现MIT组测得的实验值并不是临界速度,而是玻色气体获得能量的最小速度,实际临界速度比测得的速度要大.通过修正玻色气体获得能量的速率公式从而得出临界速度与实验测量数据的关系,并发现修正后的临界速度的实验值符合理论值.

The key physical quantity is the critical velocity of superfluity. The MIT group tested the critical velocity of condensate by moving a laser beam through the condensate at different velocities, but its data was much small than the data of theory. In this research, the effect made by the noncondensates was considered, and it was found that the data made by experiments was not the real critical velocity, but the velocity of Bose gas got energy. The real critical velocity was bigger than the experimental data. The relation between critical velocity and experimental data by modifying the formula of energy transfer rate has been found, and it has shown that the modified experimental data agree well with the theory date.