63 research outputs found
Antiferromagnetic topological insulators in cold atomic gases
We propose a spin-dependent optical lattice potential that realizes a
three-dimensional antiferromagnetic topological insulator in a gas of cold,
two-state fermions such as alkaline earths, as well as a model that describes
the tight-binding limit of this potential. We discuss the physically observable
responses of the gas that can verify the presence of this phase. We also point
out how this model can be used to obtain two-dimensional flat bands with
nonzero Chern number.Comment: 5 page
Lattice Induced Resonances in One Dimensional Bosonic Systems
We study the resonant effects produced when a Feshbach dimer crosses a
scattering continuum band of atoms in an optical lattice. We numerically obtain
the exact spectrum of two particles in a one-dimensional lattice and develop an
effective atom-dimer Hamiltonian that accurately captures resonant effects. The
lattice-induced resonances lead to the formation of bound states simultaneously
above and below the scattering continuum and significantly modify the curvature
of the dimer dispersion relation. The nature of the atom-dimer coupling depends
strongly on the parity of the dimer state leading to a novel coupling in the
case of negative parity dimers. From the exact solutions we extract the dimer
Wannier function from which we quantitatively determine the effective
Hamiltonian parameters for a many-body description.Comment: 4 pages, 3 figures, published versio
Quench-induced Floquet topological p-wave superfluids
Ultracold atomic gases in two dimensions tuned close to a p-wave Feshbach
resonance were expected to exhibit topological superfluidity, but these were
found to be experimentally unstable. We show that one can induce a topological
Floquet superfluid if weakly interacting atoms are brought suddenly close
("quenched") to such a resonance, in the time before the instability kicks in.
The resulting superfluid possesses Majorana edge modes, yet differs from a
conventional Floquet system as it is not driven externally. Instead, the
periodic modulation is self-generated by the dynamics.Comment: 5+5 pages, 2 figure
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