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TT: Fachverband Tiefe Temperaturen
TT 40: Poster Session Correlated Electrons
TT 40.90: Poster
Mittwoch, 13. März 2013, 15:00–19:00, Poster D
Long limit of momentum distribution functions in the sudden expansion a spin-imbalanced Fermi gas in one dimension — •Fabian Heidrich-Meisner1,2, Carlos Bolech3, Stephan Langer1,4, Ian McCulloch5, Giuliano Orso6, and Marcos Rigol7 — 1LMU Munich — 2FAU Erlangen-Nuremberg — 3University of Cinncinati, USA — 4University of Pittsburgh, USA — 5University of Queensland, St Lucia, Australia — 6Universite Paris-Diderot, France — 7Georgetown University, USA
We study the sudden expansion of a spin-imbalanced Fermi gas with attractive interactions in an
optical lattice after quenching the trapping potential to zero [1]. The initial state is of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) type, i.e., a quasi-
condensate of fermionic pairs that is modulated in real space. Using time-dependent DMRG, we demonstrate that the momentum distribution functions
(MDFs) of majority and minority fermions become stationary after surprisingly short expansion
times. This behavior can be understood in terms of a quantum distillation process [2] that leads
to a spatial demixing of pairs and excess fermions. As a consequence, the FFLO correlations are
rapidly destroyed. The expansion nevertheless yields
relevant information on the initial state: we argue that the asymptotic form of the MDFs is
directly related to the distribution of the Bethe-ansatz rapidities that characterize the
initial conditions for this integrable model.
[1] C. Bolech et al., Phys. Rev. Lett. 109, 110602 (2012)
F. Heidrich-Meisner et al., Phys. Rev. A 80, 041603(R) (2009)