Excitation spectrum and structure factor of a two-component Bose-Einstein condensate in different hyperfine states  

作　　者：韩玉峰 陈良 刘厚通 黄仙山 

机构地区：[1]Department of Mathematics and Physics, Anhui University of Technology [2]Department of Modern Physics, University of Science and Technology of China

出　　处：《Chinese Physics B》2013年第8期290-297,共8页中国物理B（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.10974189,10675114,10675115,and 41075027);the Natural Science College Key Projects of Anhui Province,China(Grant No.KJ2011A040)

摘　　要：The elementary excitation spectrum of a two-component Bose-Einstein condensate in different hyperfine states is obtained by Green＇s function method. It is found to have two branches. In the long wave-length limit, the two branches of the excitation spectrum are reduced to one phonon excitation and one single-particle excitation. The single-particle one has an energy gap. When the energy gap exists, we study the Landau critical velocity and the depletion of the condensate. With the obtained Green＇s functions, we calculate the structure factor of a two-component condensate. It is found that the static structure factor comprises only the branch of the phonon excitation and the single-particle excitation makes no contribution to the structure factor.The elementary excitation spectrum of a two-component Bose-Einstein condensate in different hyperfine states is obtained by Green＇s function method. It is found to have two branches. In the long wave-length limit, the two branches of the excitation spectrum are reduced to one phonon excitation and one single-particle excitation. The single-particle one has an energy gap. When the energy gap exists, we study the Landau critical velocity and the depletion of the condensate. With the obtained Green＇s functions, we calculate the structure factor of a two-component condensate. It is found that the static structure factor comprises only the branch of the phonon excitation and the single-particle excitation makes no contribution to the structure factor.

关 键 词：elementary excitation Bose-Einstein condensate structure factor 

分 类 号：O469[理学—凝聚态物理]