Gauge fields for ultracold atoms in optical superlattices

Abstract

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