Non-universal BCS-BEC crossover in resonantly interacting Fermi gases

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dc.creatorJensen, L. M.
dc.date2004-12-16
dc.date.accessioned2026-07-07T03:02:45Z
dc.date.available2026-07-07T03:02:45Z
dc.descriptionWe investigate the non-universal behavior of the BCS-BEC crossover model at the normal to superfluid transition. By using a finite temperature quantum field theoretical approach due to Nozieres and Schmitt-Rink and by making the effective range expansion of the effective two-body interaction we numerically calculate the crossover transition temperature as a function of the scattering length, $a_{F},$ and the effective range parameter, $r_{\mathrm{e}}.$ In an ultracold two-component atomic Fermi gas BCS-BEC crossover physics is expected to appear near magnetic-field-induced Feshbach resonances. By matching two-body scattering properties near a Feshbach resonance to a simple renormalized model potential, a broad resonance is characterized by a small effective range and the gas displays a universal BCS-BEC crossover behavior. On the other hand, for a narrow resonance thermodynamic quantities depend the effective range which may be large and negative at resonance. For increasing values of $-r_{\mathrm{e}}$ we find the transition temperature to be suppressed in the crossover region. We furthermore argue for existence of a lower bound of $T_{c}$ at fixed coupling for increasing $-r_{\mathrm{e}}$ in the crossover region.
dc.description8 pages, 3 figures
dc.identifierhttps://arxiv.org/abs/cond-mat/0412431
dc.identifierhttp://arxiv.org/abs/cond-mat/0412431
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/25505
dc.subjectSuperconductivity
dc.subjectStatistical Mechanics
dc.titleNon-universal BCS-BEC crossover in resonantly interacting Fermi gases
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