Particle-hole fluctuations in BCS-BEC crossover
- Institut fuer Theoretische Physik, Philosophenweg 16, D-69120 Heidelberg (Germany)
- Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, A-6020 Innsbruck (Austria)
The effect of particle-hole fluctuations for the BCS-BEC crossover is investigated by use of functional renormalization. We compute the Gorkov effect and the critical temperature for the whole range in the scattering length a. On the BCS side for small negative a we recover the Gorkov approximation, while on the BEC side of small positive a the particle-hole fluctuations play no important role, and we find a system of interacting bosons. In the unitarity limit of infinite scattering length our quantitative estimate yields T{sub c}/T{sub F}=0.264. We also investigate the crossover from broad to narrow Feshbach resonances - for the latter we obtain T{sub c}/T{sub F}=0.204 for a{sup -1}=0. A key ingredient for our treatment is the computation of the momentum dependent four-fermion vertex and its bosonization in terms of an effective bound-state exchange.
- OSTI ID:
- 21192478
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 78, Issue 17; Other Information: DOI: 10.1103/PhysRevB.78.174528; (c) 2008 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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