Equation of state of an interacting Bose gas at finite temperature: a Path Integral Monte Carlo study

TL;DR

This study employs Path Integral Monte Carlo methods to accurately determine the equation of state of an interacting Bose gas across various temperatures, revealing universal behavior and validating results against other theoretical approaches.

Contribution

It provides the first comprehensive finite-temperature equation of state for an interacting Bose gas using exact Monte Carlo techniques, exploring universality and comparing with virial expansion and diffusion Monte Carlo results.

Findings

Universal equation of state for dilute Bose gases at low temperatures

Agreement with diffusion Monte Carlo results at near-zero temperatures

Validation of virial expansion for high-temperature regimes

Abstract

By using exact Path Integral Monte Carlo methods we calculate the equation of state of an interacting Bose gas as a function of temperature both below and above the superfluid transition. The universal character of the equation of state for dilute systems and low temperatures is investigated by modeling the interatomic interactions using different repulsive potentials corresponding to the same s-wave scattering length. The results obtained for the energy and the pressure are compared to the virial expansion for temperatures larger than the critical temperature. At very low temperatures we find agreement with the ground-state energy calculated using the diffusion Monte Carlo method.