Finite-size effect of a weakly interacting Bose gas at zero-temperature

Abstract

We investigate the quantum fluctuation of a weakly interacting Bose gas confined between two parallel plates at zero temperature within two-loop approximation of the Cornwall-Jackiw-Tomboulis (CJT) effective action approach. The finite-size and boundary condition (BC) effects in the excitation atomic density, energy density, chemical potential, and sound speed are determined, including the prediction of a first-order phase transition phenomenon.