Hydrodynamic quantization approach to Bose-Einstein condensation

In this paper we employ the hydrodynamic quantization approach to studying the macroscopic state occupation of a bosonic system. We propose that the condensed state is a coherent state of the phase field component associated with the quantized field operator. By making Ansätze on functional states, we transform the problem of finding the phase and density associated with the condensate into a variational problem. We also discuss some properties of the condensed state, like superfluidity. In close analogy with Bose-Einstein condensation in the p⃗=0 state, we propose some possible wave functions for the excited states of a condensed system.