The effective mass of ultracold atoms in one-dimensional optical lattices

Xiaoming Cai

Michiel Snoek, Walter Hofstetter

We analyze the dynamics of ultracold atoms in optical lattices induced by a sudden shift of the underlying harmonic trapping potential. In order to study the effect of strong interactions, dimensionality, and lattice topology on transport properties, we consider bosonic atoms with arbitrarily strong repulsive interactions on a two-dimensional square lattice and a hexagonal lattice. On the square lattice we find insulating behavior for weakly interacting atoms and slow relaxation for strong interactions, even when a Mott plateau is present, which in one dimension blocks the dynamics. On the hexagonal lattice the center of mass relaxes to the new equilibrium for any interaction strength.

Immanuel Bloch

Immanuel Bloch, P. Zoller

Luca Lepori, Giuseppe Mussardo, Andrea Trombettoni

We propose the experimental realization of (3+1) relativistic Dirac fermions using ultracold atoms in a rotating optical lattice or, alternatively, in a synthetic magnetic field. This approach has the advantage to give mass to the Dirac fermions by coupling the ultracold atoms to a Bragg pulse. A dimensional crossover from (3+1) to (2+1) Dirac fermions can be obtained by varying the anisotropy of the lattice. We also discuss under which conditions the interatomic potentials give rise to relativistically invariant interactions among the Dirac fermions.

Dong Dong, Ming Gong, Xu‐Bo Zou +1 more

We propose a new method to control the directed quantum transport of ultracold atoms in a one-dimensional optical lattice. In this proposal, the effective tunneling between the neighboring sites can be adjusted via coherent destruction of tunneling by tuning the phase of the external field, instead of using the driving field intensity or the frequency, thus the directed quantum transport of ultracold atoms can be coherently controlled in a much easier manner. Our proposal overcomes the major drawback of the method used by Creffield et al. [ Phys. Rev. Lett. 99 (2007) 110501 ], and can be implemented, in principle, in any one-dimensional optical lattice. Some potential applications of the scheme are also discussed.