BCS-BEC crossover with unequal-mass fermions

Journal Article · Mon Mar 15 04:00:00 EDT 2010 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.81.033608· OSTI ID:21408468

Diener, Roberto B; Randeria, Mohit ^[1]

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1. Department of Physics, Ohio State University, Columbus, Ohio 43210 (United States)

We investigate the crossover from BCS pairing to molecular Bose-Einstein condensation (BEC) in an atomic gas with two fermion species with masses m{sub {up_arrow}{ne}m{down_arrow}}tuned through a Feshbach resonance. We present results for the T=0 equation of state as a function of the scattering length including the effects of Gaussian fluctuations about the mean field ground state. We compute the ground state energy as a function of m{sub {up_arrow}/}m{sub {down_arrow}}at unitarity and find excellent agreement with the quantum Monte Carlo result for m{sub {up_arrow}/}m{sub {down_arrow}=}6.67 for a {sup 40}K-{sup 6}Li mixture. We show that the dimer scattering length in the BEC limit as a function of m{sub {up_arrow}/}m{sub {down_arrow}}compares well with the exact four-body results of Petrov et al. [J. Phys. B 38, S645 (2005)]. We also derive the condition for trapping frequencies to obtain an unpolarized gas in a harmonic trap.

• OSTI ID: 21408468
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 3 Vol. 81; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

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71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
74 ATOMIC AND MOLECULAR PHYSICS
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BETA-MINUS DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BOSE-EINSTEIN CONDENSATION
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ENERGY LEVELS
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MANY-BODY PROBLEM
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