Analytical Method for yrast line states in interacting Bose-Einstein condensates

We propose a method to investigate the energy eigenvalue problem and corres ponding yrast line for harmonically trapped interacting N-boson systems. Th is method is particularly simple and effective to obtain the explicit analy tical expressions of low-L energy eigenstates with L denoting systems' tota l angular momentum but with an arbitrarily large N. We have derived the exp licit analytical results for L = 0, 1,...,9 and discussed the yrast line fo r these low-L energy eigenstates.