Article
BCSBEC Crossover of a Quasitwodimensional Fermi Gas: the Significance of Dressed Molecules
Physical Review A (Impact Factor: 2.99). 04/2008; DOI: 10.1103/PhysRevA.77.063613
Source: arXiv

Article: Significance of dressed molecules in a quasitwodimensional Fermi gas with spinorbit coupling
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ABSTRACT: We investigate the properties of a spinorbit coupled quasitwodimensional Fermi gas with tunable swave interaction between the two spin species. By analyzing the twobody bound state, we find that the population of the excited states in the tightly confined axial direction can be significant when the twobody binding energy becomes comparable to or exceeds the axial confinement. Since the Rashba spinorbit coupling that we study here tends to enhance the twobody binding energy, this effect can become prominent at unitarity or even on the BCS side of the Feshbach resonance. To study the impact of these excited modes along the third dimension, we adopt an effective twodimensional Hamiltonian in the form of a twochannel model, where the dressed molecules in the closed channel consist of the conventional Feshbach molecules as well as the excited states occupation in the axial direction. With properly renormalized interactions between atoms and dressed molecules, we find that both the density distribution and the phase structure in the trap can be significantly modified near a wide Feshbach resonance. In particular, the stability region of the topological superfluid phase is increased. Our findings provide a proper description for a quasitwodimensional Fermi gas under spinorbit coupling, and are helpful for the experimental search for the topological superfluid phase in ultracold Fermi gases.Physical Review A 03/2013; 87(3). · 2.99 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We follow the evolution of fermion pairing in the dimensional crossover from threedimensional to twodimensional as a strongly interacting Fermi gas of ^{6}Li atoms becomes confined to a stack of twodimensional layers formed by a onedimensional optical lattice. Decreasing the dimensionality leads to the opening of a gap in radiofrequency spectra, even on the BardeenCooperSchrieffer side of a Feshbach resonance. The measured binding energy of fermion pairs closely follows the theoretical twobody binding energy and, in the twodimensional limit, the zerotemperature meanfield BoseEinsteincondensation to BardeenCooperSchrieffer crossover theory.Physical Review Letters 01/2012; 108(4):045302. · 7.73 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We investigate the properties of a spinorbit coupled quasitwodimensional Fermi gas with tunable swave interaction between the two spin species. By analyzing the twobody bound state, we find that the population of the excited states in the tightlyconfined axial direction can be significant when the twobody binding energy becomes comparable or exceeds the axial confinement. Since the Rashba spinorbit coupling that we study here tends to enhance the twobody binding energy, this effect can become prominent at unitarity or even on the BCS side of the Feshbach resonance. To study the impact of these excited modes along the third dimension, we adopt an effective twodimensional Hamiltonian in the form of a twochannel model, where the dressed molecules in the closed channel consist of the conventional Feshbach molecules as well as the excited states occupation in the axial direction. With properly renormalized interactions between atoms and dressed molecules, we find that both the density distribution and the phase structure in the trap can be significantly modified near a wide Feshbach resonance. In particular, the stability region of the topological superfluid phase is increased. Our findings are helpful for the experimental search for the topological superfluid phase in ultracold Fermi gases, and have interesting implications for quasilowdimensional polarized Fermi gases in general.09/2012;
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