Condensate and superfluid fraction of homogeneous Bose gases in a self-consistent Popov approximation

Year: 2024

Authors: Vianello C., Salasnich L.

Autors Affiliation: Univ Padua, Dept Phys & Astron Galileo Galilei, Via Marzolo 8, I-35131 Padua, Italy; Univ Padua, Padua QTech Ctr, Via Gradenigo 6-A, I-35131 Padua, Italy; Natl Inst Nucl Phys INFN, Padova Sect, Via Marzolo 8, I-35020 Padua, Italy; Natl Res Council CNR, Natl Inst Opt INO, Via Nello Carrara 2, I-50127 Sesto Fiorentino, Italy.

Abstract: We study the condensate and superfluid fraction of a homogeneous gas of weakly interacting bosons in three spatial dimensions by adopting a self-consistent Popov approximation, comparing this approach with other theoretical schemes. Differently from the superfluid fraction, we find that at finite temperature the condensate fraction is a non-monotonic function of the interaction strength, presenting a global maximum at a characteristic value of the gas parameter, which grows as the temperature increases. This non-monotonic behavior has not yet been observed, but could be tested with the available experimental setups of ultracold bosonic atoms confined in a box potential. We clearly identify the region of parameter space that is of experimental interest to look for this behavior and provide explicit expressions for the relevant observables. Finite size effects are also discussed within a semiclassical approximation.

Journal/Review: SCIENTIFIC REPORTS

Volume: 14 (1)      Pages from: 15034-1  to: 15034-10

More Information: The authors thank A. Pelster and R. P. Smith for useful discussions. L. S. is partially supported by the European Union-NextGenerationEU within the National Center for HPC, Big Data and Quantum Computing [Project No. CN00000013, CN1 Spoke 10: Quantum Computing], by the BIRD Project Ultracold atoms in curved geometries of the University of Padova, by Iniziativa Specifica Quantum of Istituto Nazionale di Fisica Nucleare, by the European Quantum Flagship Project PASQuanS 2, and by the PRIN 2022 Project Quantum Atomic Mixtures: Droplets, Topological Structures, and Vortices of the Italian Ministry for University and Research (MUR). Administrative and logistic supp ort by the MUR project Dipartimenti di Eccellenza: Frontiere Quantistiche is also acknowledged.
KeyWords: Einstein Condensation; Phase-diagram
DOI: 10.1038/s41598-024-65897-2

Citations: 1
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