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  • Letter
  • Open Access

Equation of state of Bose gases beyond the universal regime

Martí Planasdemunt-Hospital, Jordi Pera*, and Jordi Boronat†

  • *Contact author: jordi.pera@upc.edu
  • †Contact author: jordi.boronat@upc.edu
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Phys. Rev. Research 6, L042071 – Published 30 December, 2024

DOI: https://doi.org/10.1103/PhysRevResearch.6.L042071

Abstract

The equation of state of dilute Bose gases, in which the energy only depends on the s-wave scattering length, is rather unknown beyond the universal limit. We have carried out a set of diffusion Monte Carlo calculations up to gas parameters of 10−2 to explore how the departure from the universality emerges. Using different model potentials, we calculate the energies of the gas in an exact way, within some statistical noise, and report the results as a function of the three relevant scattering parameters: the s-wave scattering length a0, the s-wave effective range r0, and the p-wave scattering length a1. If the effective range is not large, we observe universality in terms of a0 and r0 up to gas parameters of 10−2. If r0 grows, the regime of universality in these two parameters is reduced and effects of a1 start to be observed. In the (a0,r0) universal regime we propose an analytical law that reproduces fairly well the exact energies.

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References (32)

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Phys. Rev. Research 6, L042071– Published 30 December, 2024
  • Received 29 July 2024
  • Accepted 13 December 2024
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