Bose gases near resonance: Renormalized interactions in a condensate

Journal Article · Tue Jan 15 04:00:00 EST 2013 · Annals of Physics (New York)

DOI:https://doi.org/10.1016/J.AOP.2012.09.005· OSTI ID:22157059

Zhou, Fei; Mashayekhi, Mohammad S.

Bose gases at large scattering lengths or beyond the usual dilute limit for a long time have been one of the most challenging problems in many-body physics. In this article, we investigate the fundamental properties of a near-resonance Bose gas and illustrate that three-dimensional Bose gases become nearly fermionized near resonance when the chemical potential as a function of scattering lengths reaches a maximum and the atomic condensates lose metastability. The instability and accompanying maximum are shown to be a precursor of the sign change of g{sub 2}, the renormalized two-body interaction between condensed atoms. g{sub 2} changes from effectively repulsive to attractive when approaching resonance from the molecular side, even though the scattering length is still positive. This occurs when dimers, under the influence of condensates, emerge at zero energy in the atomic gases at a finite positive scattering length. We carry out our studies of Bose gases via applying a self-consistent renormalization group equation which is further subject to a boundary condition. We also comment on the relation between the approach here and the diagrammatic calculation in an early article [D. Borzov, M.S. Mashayekhi, S. Zhang, J.-L. Song, F. Zhou, Phys. Rev. A 85 (2012) 023620]. - Highlights: Black-Right-Pointing-Pointer A Bose gas becomes nearly fermionized when its chemical potential approaches a maximum near resonance. Black-Right-Pointing-Pointer At the maximum, an onset instability sets in at a positive scattering length. Black-Right-Pointing-Pointer Condensates strongly influence the renormalization flow of few-body running coupling constants. Black-Right-Pointing-Pointer The effective two-body interaction constant changes its sign at a positive scattering length.

• OSTI ID: 22157059
• Journal Information: Annals of Physics (New York), Journal Name: Annals of Physics (New York) Vol. 328; ISSN 0003-4916; ISSN APNYA6
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ATOMS
BOSE-EINSTEIN CONDENSATION
BOSE-EINSTEIN GAS
BOUNDARY CONDITIONS
COUPLING CONSTANTS
DIMERS
INTERATOMIC FORCES
POTENTIALS
RENORMALIZATION
SCATTERING LENGTHS
THREE-DIMENSIONAL CALCULATIONS
TWO-BODY PROBLEM