简谐势阱中的理想玻色气体

应用统计物理方法对谐振势作用下的理想玻色气体进行理论计算，导出系统发生玻色－爱因斯坦凝聚（ＢＥＣ）时的一些物理量，发现产生凝聚的情况与外势场的形式紧密相关．由理论计算求得的临界温度ＴＣ和基态的粒子占据率Ｎ０／Ｎ与实验结果符合较好．这些研究有助于对这种新物态性质的了解．

Electronic Raman Scattering, Bound Phonons and DX Centers in n Ga 1-x Al x As

The first observation of electronic Raman scattering and bound phonons in n Ga 1-x Al x As is reported. Raman scattering experiments performed on n Ga 1-x Al x As samples reveal that there exists an effective mass like level for donor impurities giving rise to the bound phonons and the electronic Raman scattering at low temperatures and beyond some critical value of the alloy composition in n Ga 1-x Al x As.At higher temperatures, this level is depopulated to the benefit of a deep state which has all the characteristics of DX center. These results validate as well a shallow deep bistable character of n type impurities in Ga 1-x Al x As( x >0.45).According to the dynamical theory of crystal lattices, the tharge state of donors in Ga 1-x Al x As has been simply explained.