arXiv:0911.4026 · Physics Reports

Solution of the Bogoliubov–de Gennes equations at zero temperature throughout the BCS–BEC crossover: Josephson and related effects

A. Spuntarelli, P. Pieri, Giancarlo Calvanese Strinati

Published Dec 7, 2009• 69 citations

DOI: 10.1016/j.physrep.2009.12.005

Related papers

Josephson Effect throughout the BCS-BEC Crossover

Andrea Spuntarelli, P. Pieri, Giancarlo Calvanese Strinati

We study the stationary Josephson effect for neutral fermions across the BCS-BEC (Bose-Einstein condensate) crossover, by solving numerically the Bogoliubov-de Gennes equations at zero temperature. The Josephson current is found to be considerably enhanced for all barriers at about unitarity. For vanishing barrier, the Josephson critical current approaches the Landau limiting value which, depending on the coupling, is determined by either pair-breaking or sound-mode excitations. In the coupling range from the BCS limit to unitarity, a procedure is proposed to extract the pairing gap from the Landau limiting current.

arXiv:0705.2658Physical Review LettersJul 23, 200764 citations

STATIONARY JOSEPHSON EFFECT IN THE BCS-BEC CROSSOVER

Andrea Spuntarelli, P. Pieri, Giancarlo Calvanese Strinati

Recent Progress in Many-Body TheoriesJun 1, 20080 citations

Equation for the superfluid gap obtained by coarse graining the Bogoliubov–de Gennes equations throughout the BCS-BEC crossover

Stefano Simonucci, Giancarlo Calvanese Strinati

We derive a nonlinear differential equation for the gap parameter of a superfluid Fermi system by performing a suitable coarse graining of the Bogoliubov--de Gennes (BdG) equations throughout the BCS-BEC crossover, with the aim of replacing the time-consuming solution of the original BdG equations by the simpler solution of this novel equation. We perform a favorable numerical test on the validity of this new equation over most of the temperature-coupling phase diagram, by an explicit comparison with the full solution of the original BdG equations for an isolated vortex. We also show that the new equation reduces both to the Ginzburg-Landau equation for Cooper pairs in weak coupling close to the critical temperature and to the Gross-Pitaevskii equation for composite bosons in strong coupling at low temperature.

arXiv:1402.4954Physical Review BFeb 19, 201428 citations

Field-theoretical description of the crossover between BCS and BEC in a non-Fermi superconductor

Cătălin Paşcu Moca, M. Crişan, E. MACOCIAN +1 more

arXiv:cond-mat/9904197Journal of Physics and Chemistry of SolidsJan 30, 20030 citations

TACKLING FLUCTUATION CORRECTIONS IN THE BEC/BCS CROSSOVER AT NONZERO TEMPERATURES

Jacques Tempere, Serghei N. Klimin, J. T. Devreese

International Conference on Path IntegralsNov 1, 20080 citations

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

Yong-li Ma, Guoxiang Huang

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.

Physical Review AJun 27, 200719 citations