Magnetic tuning of the relativistic BCS-BEC crossover

作者:Wang Jin cheng*; de la Incera Vivian; Ferrer Efrain J; Wang Qun
来源:Physical Review D - Particles, Fields, Gravitation and Cosmology, 2011, 84(6): 065014.
DOI:10.1103/PhysRevD.84.065014

摘要

The effect of an applied magnetic field in the crossover from Bose-Einstein condensate (BEC) to Bardeen-Cooper-Schrieffer (BCS) pairing regimes is investigated. We use a model of relativistic fermions and bosons inspired by those previously used in the context of cold fermionic atoms and in the magnetic-color-flavor-locking phase of color superconductivity. It turns out that, as with cold atom systems, an applied magnetic field can also tune the BCS-BEC crossover in the relativistic case. We find that no matter what the initial state is at B = 0, for large enough magnetic fields the system always settles into a pure BCS regime. In contrast to the atomic case, the magnetic field tuning of the crossover in the relativistic system is not connected to a Feshbach resonance, but to the relative numbers of Landau levels with either BEC or BCS type of dispersion relations that are occupied at each magnetic field strength.