BEC-BCS Crossover in the Epsilon Expansion Export

@misc{citeulike:891078, abstract = {The epsilon expansion (expansion around four spacial dimensions) developed by Nishida and Son for a cold fermi gas with infinite scattering length is extended to finite scattering length to study the BEC-BCS crossover. A resummation of higher order logarithms and a suitable extension of fermion coupling in d-dimensions are developed in order to apply the theory in the BCS regime. The ratio between the chemical potential and the Fermi energy, mu/eF, is computed to next-to-leading order in the epsilon expansion as a function of eta=1/(a kF), where a is the scattering length and kF is the Fermi momentum in a non-interacting system. Near the unitarity limit eta-\>0, we found mu/eF=0.475-0.707 eta-0.5 eta^2. Near the BEC limit eta-\>infinity, mu/eF=0.062/eta - eta^2, while near the BCS limit eta-\>-infinity, mu/eF=1+0.707/eta. Overall good agreement with Quantum Monte Carlo results is found.}, archivePrefix = {arXiv}, author = {Chen, Jiunn-Wei and Nakano, Eiji}, citeulike-article-id = {891078}, citeulike-linkout-0 = {http://arxiv.org/abs/cond-mat/0610011}, citeulike-linkout-1 = {http://arxiv.org/pdf/cond-mat/0610011}, day = {1}, eprint = {cond-mat/0610011}, keywords = {epsilon, expansion, fermi\_gas, unitary}, month = {Oct}, posted-at = {2006-10-10 08:06:37}, priority = {3}, title = {BEC-BCS Crossover in the Epsilon Expansion}, url = {http://arxiv.org/abs/cond-mat/0610011}, year = {2006} }

TY - ELEC ID - citeulike:891078 L3 - citeulike-article-id:891078 N2 - The epsilon expansion (expansion around four spacial dimensions) developed by Nishida and Son for a cold fermi gas with infinite scattering length is extended to finite scattering length to study the BEC-BCS crossover. A resummation of higher order logarithms and a suitable extension of fermion coupling in d-dimensions are developed in order to apply the theory in the BCS regime. The ratio between the chemical potential and the Fermi energy, mu/eF, is computed to next-to-leading order in the epsilon expansion as a function of eta=1/(a kF), where a is the scattering length and kF is the Fermi momentum in a non-interacting system. Near the unitarity limit eta->0, we found mu/eF=0.475-0.707 eta-0.5 eta^2. Near the BEC limit eta->infinity, mu/eF=0.062/eta - eta^2, while near the BCS limit eta->-infinity, mu/eF=1+0.707/eta. Overall good agreement with Quantum Monte Carlo results is found. TI - BEC-BCS Crossover in the Epsilon Expansion KW - epsilon KW - expansion KW - fermi_gas KW - unitary AU - Chen, Jiunn-Wei AU - Nakano, Eiji PY - 2006/Oct/01/ UR - http://arxiv.org/abs/cond-mat/0610011 ER -