Mott Phase in Polarized Two-component Atomic Fermi Lattice Gas:A   Playground for S=1/2 Heisenberg Model in Magnetic Field
  We investigate effects of pseudo-spin population imbalance on Mott phases in 1D trapped two-component atomic Fermi gases loaded on optical lattices based on the repulsive Hubbard model in harmonic traps. By using the density matrix renormalization group method, we numerically calculate density profiles of each component and clarify the pseudo-spin magnetism. Consequently, we find that all the features from weakly imbalance to fully polarized cases are well described by S=1/2 antiferromagnetic Heisenberg chain under magnetic field. These results indicate that the Mott phases offer experimental stages for studying various interacting spin systems. 
M. Machida, M. Okumura, S. Yamada, T. Deguchi, Y. Ohashi, H. Matsumoto