Bogoliubov excitations of trapped superfluid Fermi gases in a BCS-BEC crossover beyond the Thomas-Fermi limit

Journal Article · Fri Jun 15 00:00:00 EDT 2007 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.75.063629· OSTI ID:21000514

Yongli, Ma; Guoxiang, Huang ^[1]

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1. Department of Physics, Fudan University, Shanghai 200433 (China)

We study the Bogoliubov collective excitations of harmonically trapped superfluid Fermi gases in the crossover from Bardeen-Cooper-Schrieffer (BCS) superfluid to Bose-Einstein condensate (BEC) beyond Thomas-Fermi (TF) limit. Starting from a generalized Gross-Pitaevskii equation and an equation of state valid for the whole crossover, we derive Bogoliubov-de Gennes (BdG) equations for low-lying collective modes at zero temperature. We use a Fetter-like variational ground state wave function to remove the noncontinuity of slope at the boundary of condensate, which appears in the TF limit. We solve the BdG equations analytically and obtain explicit expressions for all eigenvalues and eigenfunctions, valid for various crossover regimes and for traps with spherical and axial symmetries. We discuss the feature of these collective excitations in the BCS-BEC crossover and show that the theoretical result obtained agrees with available experimental data near and beyond the TF limit.

• OSTI ID: 21000514
• Journal Information: Physical Review. A, Vol. 75, Issue 6; Other Information: DOI: 10.1103/PhysRevA.75.063629; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANALYTICAL SOLUTION
AXIAL SYMMETRY
BCS THEORY
BOGOLYUBOV METHOD
BOSE-EINSTEIN CONDENSATION
COLLECTIVE EXCITATIONS
CONDENSATES
EIGENFUNCTIONS
EIGENVALUES
EQUATIONS OF STATE
FERMI GAS
FERMIONS
GROUND STATES
SPHERICAL CONFIGURATION
SUPERFLUIDITY
THOMAS-FERMI MODEL
TRAPPING
TRAPS
VARIATIONAL METHODS
WAVE FUNCTIONS