Regensburg 2004 – scientific programme
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TT: Tiefe Temperaturen
TT 4: Quantenflüssigkeiten, Bose-Einstein Kondensate, ultrakalte Atome, ...
TT 4.4: Talk
Monday, March 8, 2004, 11:00–11:15, H19
Ultracold fermions and the SU(N) Hubbard model — •Carsten Honerkamp1 and Walter Hofstetter2 — 1MPI Solid State Research, Stuttgart — 2MIT, Cambridge, USA
We investigate the fermionic SU(N) Hubbard model on the two-dimensional square lattice for weak to moderate interaction strengths using one-loop renormalization group and mean-field methods. For the repulsive case U>0 at half filling and small N the dominant tendency is towards breaking of the SU(N) symmetry. For N>6 staggered flux order takes over as the dominant instability, in agreement with the large-N limit. Away from half filling for N=3 the system rearranges the particle densities such that two flavors remain half filled by cannibalizing the third flavor. In the attractive case and odd N a full Fermi surface coexists with a superconductor in the ground state. These results may be relevant to future experiments with cold fermionic atoms in optical lattices.