Thermodynamics of a dilute Bose gas: A path-integral Monte Carlo study

Year: 2022

Authors: Spada G.; Pilati S.; Giorgini S.

Autors Affiliation: 1Dipartimento di Fisica, Universita di Trento and CNR-INO BEC Center, 38123 Povo, Trento, Italy; School of Science and Technology, Physics Division, Universita di Camerino, 62032 Camerino, Italy; INFN, Sezione di Perugia, 06123 Perugia, Italy

Abstract: We present precise path-integral Monte Carlo results for the thermodynamics of a homogeneous dilute Bose gas. Pressure and energy are calculated as a function of temperature both below and above the Bose-Einstein transition. Specifically, we address interaction effects, focusing on deviations from the ideal-gas law in the thermodynamic limit. We also calculate the isothermal compressibility and the contact parameter, which provide a clear signature of the role played by interactions. In particular, we obtain indications of a discontinuity of the compressibility at the transition point. To gain physical insight, numerical results are systematically compared with the predictions of first-order Hartree-Fock and second-order Popov theories, both giving an approximate description of the gas thermodynamics. The comparison shows the extension of the critical region around the transition point, where the inaccuracies of the perturbative expansions are more pronounced.


Volume: 105 (1)      Pages from: 013325-1  to: 013325-9

More Information: This work was supported by the Italian Ministry of Uni-versity and Research under the PRIN2017 project CEnTraL 20172H2SC4. S.P. acknowledges PRACE for awarding ac-cess to the Fenix Infrastructure resources at Cineca, which are partially funded by the European Union´s Horizon 2020 research and innovation program through the ICEI project under Grant Agreement No. 800858. S.P. also acknowl-edges the Cineca award under the ISCRA initiative for the availability of high performance computing resources and support. The authors would like to thank F. Werner for fruitful discussions.
KeyWords: heat-capacity; ground-state; quantum
DOI: 10.1103/PhysRevA.105.013325