囚禁势中玻色-爱因斯坦凝聚体的半轴宽度和粒子数密度

文章计算了准一维、准二维、球对称、轴对称系统的玻色-爱因斯坦凝聚体的半轴宽度和粒子数密度,采用求基态能量极小值和令势能等于相互作用能的办法,讨论的问题包括凝聚体半轴宽度的解析表达式、粒子数密度的理论计算值与实验数据的对比分析和吸引相互作用系统的塌缩粒子数。     

Landau damping of collective mode in a quasi-two-dimensional repulsive Bose-Einstein condensate

We investigate the Landau damping of the collective mode in a quasi-two-dimension repulsive Bose-Einstein condensate by using the self-consistent time-dependent Hatree-Fock-Bogoliubov approximation and a complete and orthogonal eigenfunction set for the elementary excitation of the system.We calculate the three-mode coupling matrix element between the collective mode and the thermal excited quasi-particles and the Landau damping rate of the collective mode.We discuss the dependence of the Landau damping on temperature,on atom number in the condensate,on transverse trapping frequency and on the length of the condensate.The energy width of the collective mode is taken into account in our calculation.With little approximation,our theoretic calculation results agree well with the experimental ones and are helpful for deducing the damping mechanics and the inter-particle interaction.     

开尔文电桥测电阻及用Visual Basic处理测量数据

用开尔文电桥测量金属棒的电阻率时,电阻率的不确定度是由测量金属棒直径、长度和电阻的不确定度来决定。为了又快又准确地处理实验的测量数据,设计编制了Visual Basic程序,从而方便快捷的计算出金属棒电阻率的不确定度。     

光栅衍射测光波波长及用Visual Basic计算其不确定度

光栅衍射实验研究,可用于测量可见光的波长及计算其不确定度。推导了光栅常数d和波长λ的不确定度计算公式。由于不确定度的计算公式中含有分光计测量衍射角θ,考虑单位转换过程复杂,在计算波长不确定度时工作变得极其繁琐。因此,设计Visual Basic程序方便快捷地计算出了光波波长及其不确定度。     

Landau damping of collective mode in a quasi-two-dimensional repulsive Boseben Einstein condensate

We investigate the Landau damping of the collective mode in a quasi-two-dimension repulsive Bose—Einstein condensate by using the self-consistent time-dependent Hatree—Fock—Bogoliubov approximation and a complete and orthogonal eigenfunction set for the elementary excitation of the system. We calculate the three-mode coupling matrix element between the collective mode and the thermal excited quasi-particles and the Landau damping rate of the collective mode. We discuss the dependence of the Landau damping on temperature, on atom number in the condensate, on transverse trapping frequency and on the length of the condensate. The energy width of the collective mode is taken into account in our calculation. With little approximation, our theoretic calculation results agree well with the experimental ones and are helpful for deducing the damping mechanics and the inter-particle interaction.