Phase diagram and BCS-Bose condensation crossover in 1d and 2d hubbard models

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Title:	Phase diagram and BCS-Bose condensation crossover in 1d and 2d hubbard models
Authors:	楊棨;Yang, Chi;Kocharian, A. N.;Chiang, Y. L.
Contributors:	淡江大學物理學系
Keywords:	Hubbard model;Bethe-ansatz;Quantum Monte-Carlo;BCS–BC crossover
Date:	2001-11-01
Issue Date:	2009-12-31 10:40:34 (UTC+8)
Publisher:	Elsevier
Abstract:	The ground-state energy, the concentration of double occupied sites and the density of bound electron pairs in low-dimensional attractive Hubbard model are calculated by means of the generalized self-consistent field (GSCF) approach. This approach gives an excellent agreement with the corresponding Bethe-ansatz solution and the quantum Monte-Carlo calculations in a wide range of interaction strength U<0 and electron concentration n. A simple relationship is found between the order parameter and the density of bound electron pairs, valid for any dimension and in entire parameter space U, n and magnetic field h. The electron pairing and the crossover from the itinerant BCS regime into the Bose condensation regime of local pairs are studied in dependence of both U and n. The GSCF theory correctly displays the separation of the energy gap from the BCS order parameter at n≠1 as \|U\| increases.
Relation:	Physica C: superconductivity 364-365, pp.131-133
DOI:	10.1016/S0921-4534(01)00730-4
Appears in Collections:	[Graduate Institute & Department of Physics] Journal Article

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