Thermal field theory of bosonic gases with finite-range effective interaction

A. Cappellaro and L. Salasnich
Phys. Rev. A 95, 033627 – Published 27 March 2017

Abstract

We study a dilute and ultracold Bose gas of interacting atoms by using an effective field theory which takes into account the finite-range effects of the interatomic potential. Within the formalism of functional integration from the grand canonical partition function, we derive beyond-mean-field analytical results which depend on both the scattering length and the effective range of the interaction. In particular, we calculate the equation of state of the bosonic system as a function of these interaction parameters both at zero and finite temperature including one-loop Gaussian fluctuation. In the case of zero-range effective interaction, we explicitly show that, due to quantum fluctuations, the bosonic system is thermodynamically stable only for very small values of the gas parameter. We find that a positive effective range above a critical threshold is necessary to remove the thermodynamical instability of the uniform configuration. Remarkably, also for relatively large values of the gas parameter, our finite-range results are in quite good agreement with recent zero-temperature Monte Carlo calculations obtained with hard-sphere bosons.

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  • Received 13 December 2016

DOI:https://doi.org/10.1103/PhysRevA.95.033627

©2017 American Physical Society

Physics Subject Headings (PhySH)

Atomic, Molecular & OpticalStatistical Physics & Thermodynamics

Authors & Affiliations

A. Cappellaro1 and L. Salasnich1,2,3

  • 1Dipartimento di Fisica e Astronomia “Galileo Galilei,” Università di Padova, Via Marzolo 8, 35131 Padova, Italy
  • 2Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM), Unità di Padova, Via Marzolo 8, 35131 Padova, Italy
  • 3Istituto Nazionale di Ottica (INO) del Consiglio Nazionale delle Ricerche (CNR), Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy

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Issue

Vol. 95, Iss. 3 — March 2017

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