Visualizing Atom Currents in Optical Lattices

Hoseong Lee, James Clemens

Georg A. Raithel, Natalya V. Morrow

Matthew Killi, Stefan Trotzky, Arun Paramekanti

Bosons and fermions, in the presence of frustration or background gauge fields, can form manybody ground states which support equilibrium 'charge' or 'spin' currents. Motivated by the experimental creation of frustration or artificial gauge fields in ultracold atomic systems, we propose a general scheme by which making a sudden anisotropic quench of the atom tunneling across the lattice and tracking the ensuing density modulations provides a powerful and gauge invariant route to visualizing diverse equilibrium current patterns. Using illustrative examples of trapped superfluid Bose and normal Fermi systems in the presence of artificial magnetic fluxes on square lattices, and frustrated bosons in a triangular lattice, we show that this scheme to probe equilibrium bulk current order works independent of particle statistics. We also show that such quenches can detect chiral edge currents in gapped topological states, such as quantum Hall or quantum spin Hall insulators.

Armando Pérez-Leija, H. M. Moya-Cessa, Demetrios N. Christodoulides

A classical realization of the atom-field interaction Hamiltonian, based on the transport of light in engineered optical waveguide lattices, is theoretically proposed. The optical lattice enables direct visualization of atom-field dynamics in Fock space.

Jie-Yun Yan, Suqing Duan, Wei Zhang +1 more

The atomic current in the Fourier-synthesized optical lattices under a constant external force is investigated theoretically. Based on a two-band model, the atomic current is derived by solving the Boltzmann equations. We find that the stationary atomic current changes with the probability of Landau-Zener tunneling, depending on the adjustable energy structure of the optical lattices. In contrast to the classical results of an electron in superlattices given by the Esaki-Tsu equations, the relation between the stationary atomic current and the strength of the external force in optical lattices is modified significantly. Both these characteristics can be taken as an effective way to observe the Landau-Zener tunneling in the optical lattices.

Christopher R. Monroe