2024/07/25 by Marti Planasdemunt, Planasdemunt, Marti, Jordi Pera +3
Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Cold Atom Physics and Bose-Einstein Condensates #FOS: Physical sciences #Quantum Gases (cond-mat.quant-gas) #Quantum, superfluid, helium dynamics
paper · pdf · doi:10.48550/arxiv.2407.18059
openalex publication_date 2024/07/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
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 bunch 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.