Berlin 2014 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 63: Quantum gases: Lattices III
Q 63.3: Vortrag
Freitag, 21. März 2014, 14:30–14:45, UDL HS2002
Competing Magnetic and Superfluid Phases in the Two-Channel Fermi-Hubbard Model — •Victor Bezerra1, Flavio Nogueira2, and Axel Pelster3 — 1Department of Physics, Freie Universität Berlin, Germany — 2Department of Physics, Ruhr-Universität Bochum, Germany — 3Department of Physics and Research Center OPTIMAS, Technische Universitatät Kaiserslautern, Germany
We consider a two-channel Bose-Hubbard model where the fermions interact repulsively and the Feshbach bosons emerge from a coupling of two fermions. Within a mean-field theory at zero temperature we analyze the possibility of a competing presence of both an antiferromagnetic (AF) and an s-wave superconducting (SC) order parameter. The resulting phase diagram reveals that both phases never coexist and that the transition between them is of first order in accordance with the Ginzburg-Landau-Wilson paradigm. If the fermionic density is equal to unity, the system can be either in a SC or an AF phase depending on the respective values of the other physical parameters. For a fermionic filling different from unity we have only observed the existence of a SC phase. Such a two-channel Hubbard model could be interesting in simulating the novel pnictide high-temperature superconductors, as they also show an interplay between an AF and a SC phase.