Beyond the Gross-Pitaevskii Equation: A Perturbative Approach
We propose and implement a beyond Gross-Pitaevskii approach based on Many-Body Perturbation theory (MBPT) for the study of Bose-Einstein Condensate (BECs) ground states. Two partitions of the system Hamiltonian are considered. Firstly, a bosonic analogue to Møller-Plesset simply dubbed RSPT, and secondly an approach based on the Epstein-Nesbet partitioning scheme labeled ENPT. We consider one-dime