A. Korolyuk, D.-H. Kim, F. Massel, J.-P. Martikainen*, P. Törmä
Aalto University, Helsinki, Finland
We propose here that for a spin-imbalanced two-component attractive Fermi gas loaded in a 1D optical lattice in presence of an harmonic confining potential, the observation of the change in the double occupancy after a lattice depth modulation can provide clear evidence of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phase. Simulating the time evolution of the system, we can characterize the double occupancy spectrum for different initial conditions, relating its features to the FFLO wavevector q. In particular, the narrowing of the width of the spectrum can be related, through Bethe-ansatz equations in the strongly interacting limit, to the FFLO wavevector q. [1,2]
We will also present dynamical mean field theory (DMFT) calculations of imbalanced Fermi gases in lattices and traps of various aspect ratios. We show that the critical polarization is independent of the aspect ratio and that exotic superfluid states such as polarized superfluidity and the FFLO state appear in highly elongated traps .
 A. Korolyuk, F. Massel, P. Törmä, Probing the FFLO phase by double occupancy modulation spectroscopy, Phys. Rev. Lett. 104, 236402 (2010).
 F. Massel, M.J. Leskinen, P. Törmä, Hopping modulation in a one-dimensional Fermi-Hubbard Hamiltonian, Phys. Rev. Lett. 103, 066404 (2009).
 D.H. Kim, J.J. Kinnunen, J-P. Martikainen, P. Törmä, in preparation.
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