Gauge fields for ultracold atoms in optical superlattices

TL;DR

This paper proposes a method to generate strong, uniform artificial magnetic fields for ultracold atoms in optical lattices using laser-assisted tunneling and superlattices, enabling simulation of gauge fields and their effects.

Contribution

It introduces a scheme utilizing metastable states and optical superlattices to produce uniform U(1)-like gauge fields in 2D optical lattices, advancing quantum simulation capabilities.

Findings

Realistic implementation of uniform magnetic flux between 0 and π per plaquette.

Observable effects on non-interacting bosonic and fermionic gases.

Potential extension to non-Abelian gauge fields.

Abstract

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.