# Effective theories for cold atom systems with enhanced symmetry

Dr. Alexei Kolezhuk Institute of Magnetism , National Academy of Sciences of Ukraine, Kiev

15.06.2011 at 10:00

Effective field-theoretical description for spin-1 bosons and spin-3/2 fermions in low-dimensional optical lattices at unit filling in the Mott regime is discussed. The focus is on the physics around points/lines exhibiting enhanced SU(N) symmetry, which can be perturbed by external magnetic field.

For spin-1 bosons, the phase diagram around the ferromagnetic SU(3) point is presented and compared to the theoretical predictions. For spin-3/2 fermions in the vicinity of the staggered antiferromagnetic SU(4) point it is shown that the Sp(4) perturbation favors the ordered phase. The effects of further breaking the Sp(4) symmetry down to SU(2) are addressed.

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