Thermodynamics of the BCS-BEC crossover

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dc.creatorHaussmann, R.
dc.creatorRantner, W.
dc.creatorCerrito, S.
dc.creatorZwerger, W.
dc.date2006-08-11
dc.date2007-02-22
dc.date.accessioned2026-07-07T12:37:42Z
dc.date.available2026-07-07T12:37:42Z
dc.descriptionWe present a self-consistent theory for the thermodynamics of the BCS-BEC crossover in the normal and superfluid phase which is both conserving and gapless. It is based on the variational many-body formalism developed by Luttinger and Ward and by DeDominicis and Martin. Truncating the exact functional for the entropy to that obtained within a ladder approximation, the resulting self-consistent integral equations for the normal and anomalous Green functions are solved numerically for arbitrary coupling. The critical temperature, the equation of state and the entropy are determined as a function of the dimensionless parameter $1/k_Fa$, which controls the crossover from the BCS-regime of extended pairs to the BEC-regime of tightly bound molecules. The tightly bound pairs turn out to be described by a Popov-type approximation for a dilute, repulsive Bose gas. Even though our approximation does not capture the critical behaviour near the continuous superfluid transition, our results provide a consistent picture for the complete crossover thermodynamics which compare well with recent numerical and field-theoretic approaches at the unitarity point.
dc.descriptionpublished version
dc.identifierhttps://arxiv.org/abs/cond-mat/0608282
dc.identifierhttp://arxiv.org/abs/cond-mat/0608282
dc.identifierPhys.Rev.A75:023610,2007
dc.identifierdoi:10.1103/PhysRevA.75.023610
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/218532
dc.subjectStatistical Mechanics
dc.titleThermodynamics of the BCS-BEC crossover
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