Gauge fields for ultracold atoms in optical superlattices

Fabrice Gerbier (1, 2) , Jean Dalibard (1)

1 LKB (Lhomond) - Laboratoire Kastler Brossel
2 LKB [Collège de France] - Laboratoire Kastler Brossel

We present a scheme that produces a strong U(1)-like gauge field on cold atoms confined in a two-dimensional square optical lattice. Our proposal relies on two essential features, a long-lived metastable excited state that exists for alkaline-earth or Ytterbium atoms, and an optical superlattice. As in the proposal by Jaksch and Zoller [New Journal of Physics 5, 56 (2003)], laser-assisted tunneling between adjacent sites creates an effective magnetic field. In the tight-binding approximation, the atomic motion is described by the Harper Hamiltonian, with a flux across each lattice plaquette that can realistically take any value between 0 and $\pi$. We show how to take advantage of the superlattice to ensure that each plaquette acquires the same phase, thus simulating a uniform magnetic field. We discuss the observable consequences of the artificial gauge field on non-interacting bosonic and fermionic gases. We also outline how the scheme can be generalized to non-Abelian gauge fields.

Domaines: Gaz Quantiques [cond-mat.quant-gas]

Fabrice Gerbier, Jean Dalibard. Gauge fields for ultracold atoms in optical superlattices. New Journal of Physics, 2010, 12 (3), pp.033007. ⟨10.1088/1367-2630/12/3/033007⟩. ⟨hal-00425517v3⟩