MC simulations of $O(2){\varphi }^4$ theory in three dimensions with worm algorithm

Abstract

We study the critical region of the $O(2){\varphi }^4$ theory by means of Monte Carlo simulations on the lattice. In particular we determine the ratio $\Delta ⟨{\varphi }^2{⟩}_c/g$ in order to estimate the first correction to the critical temperature of a weak interacting Bose gas.