Wednesday, July 24, 2013

1307.6128 (Gia-Wei Chern et al.)

Dynamically generated flat-band phases in optical kagome lattices    [PDF]

Gia-Wei Chern, Chih-Chun Chien, Massimiliano Di Ventra
We suggest that a dynamically generated flat-band insulator can be realized using ultracold fermions loaded in an optical kagome lattice by depleting the mobile atoms at one edge of the lattice with a focused laser beam. Since the flat band of the kagome lattice is a high-energy one compared to the dispersive bands, this dynamically generated flat-band insulator is a population-inversion phase with no pumping required to maintain it after its formation. We also show that in a similar setup a dynamical stripe phase emerges in the flat band when two-component fermions with weakly repulsive interactions evolve in a static kagome lattice or even in the absence of interactions when the optical lattice is modulated. Given the broad variety of lattice geometries supporting frustration-induced localized states, our work opens the door to atomtronic devices utilizing geometrical effects and offers new insight on the dynamics of geometrically frustrated systems.
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