Berlin 2012 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 50: Superconductivity: (General) Theory

TT 50.7: Talk

Friday, March 30, 2012, 11:15–11:30, H 3010

Fulde-Ferrel-Larkin-Ovchinnikov phase separation in a one-dimensional superconducting lattice of strongly coupled fermions — •Vivian França and Andreas Buchleitner — Physikalisches Institut, Albert-Ludwigs Universität, Freiburg, Germany

The exotic coexistence of superconductivity and magnetism, first investigated by Fulde-Ferrell and Larkin-Ovchinnikov (FFLO), is predicted to show a spontaneous breaking of spatial symmetry. In spin-imbalanced fermionic systems, such inhomogeneous superfluidity would take place via a microscale phase separation, with alternating finite-momentum pairs and normal regions, the latter being composed by the excess species. After almost fifty years since the FFLO-phase was predicted, the microscale phase separation has not been observed.

We deduce an expression for the critical polarization below which the FFLO-state emerges in a one-dimensional lattice with spin-imbalanced populations and show that its ground-state is indeed microscale phase separated. For strongly interacting systems, we find that the microscale structure can be observed directly in the density profiles. Our results suggest that clear signatures of exotic superfluidity are accessible for state-of-the-art experiments with single-site resolution, as already achieved for bosons.