Heuristic approach to BEC self-trapping in double wells beyond   mean-field
  We present a technically simple treatment of self-trapping of Bose-Einstein condensates in double well traps based on intuitive semi-classical approximations. Our analysis finally leads to a convenient closed form approximation for the time-averaged population imbalance valid in both the mean-field case and in the case of finite particle numbers for short times. 
Kevin Rapedius
quant-ph cond-mat.quant-gas