Study of Bose-Einstein Condensates Using Perturbation Theory

摘要

We have developed and applied a perturbation approach to study Bose- Einstein condensates using a full many-body Hamiltonian. Our approach offers distinct advantages for describing a large system of N interacting identical particles. In particular, our approach has the potential to yield insight into the dynamics of motion of the condensate by defining collective coordinates at first order. Our initial many-body results for a Bose-Einstein condensate indicate that very accurate many-body results are possible using powerful group theoretic techniques with a quite modest amount of computation. This method can be applied to strongly-interacting condensates which bridge the gap between dilute condensates which can be described by mean field treatments and the regime of superfluidity/superconductivity where strong interactions make first principles treatments difficult. Characterizing condensates in the strongly interacting regime where correlation effects are important is the goal of this research.