The excitation spectrum in a weakly interacting bose gas

Abstract

Abstract In the work the problem of phenomenon of superfluidity is considered within the framework of Bose-Einshtein condensation, theoretically. We discuss the main features of the excitation spectrum in a weakly interacting Bose gas. Our analysis will show that the healing length, which determines the length scale below which collective phenomena are physically more relevant than free-particle-like ones. Since the weakly interacting gas of Bose particles has been mapped onto a gas of noninteracting quasiparticles, we are able to analyze the thermodynamics of the system and find how temperature affect the depletion of the condensate.