Ground-State Properties of a Dilute Two-Dimensional Bose Gas

摘要

We revisit the problem of the calculation of zero-temperature properties for the dilute two-dimensional Bose gas. By using Popov's hydrodynamic approach and perturbation theory on the two-loop level, we recover not only the known expansion for the ground-state energy but also calculate for the first time the condensate density and Tan's contact.