Synthetic magnetic fluxes on the honeycomb lattice

TL;DR

This paper proposes experimental methods to simulate uniform and staggered magnetic fluxes on ultracold atoms in a honeycomb lattice, enabling exploration of quantum Hall effects and Hofstadter's butterfly in cold atom systems.

Contribution

It introduces a novel scheme using Raman lasers to induce artificial magnetic fluxes in honeycomb lattices for ultracold atoms, mimicking condensed matter phenomena.

Findings

Achieves magnetic flux of about two flux quanta per unit cell.

Realizes a cold atom analogue of the Harper model.

Potential to observe quantum Hall effects in cold atom systems.

Abstract

We devise experimental schemes able to mimic uniform and staggered magnetic fluxes acting on ultracold two-electron atoms, such as ytterbium atoms, propagating in a honeycomb lattice. The atoms are first trapped into two independent state-selective triangular lattices and are further exposed to a suitable configuration of resonant Raman laser beams. These beams induce hops between the two triangular lattices and make atoms move in a honeycomb lattice. Atoms traveling around each unit cell of this honeycomb lattice pick up a nonzero phase. In the uniform case, the artificial magnetic flux sustained by each cell can reach about two flux quanta, thereby realizing a cold atom analogue of the Harper model with its notorious Hofstadter's butterfly structure. Different condensed-matter phenomena such as the relativistic integer and fractional quantum Hall effects, as observed in graphene samples, could be targeted with this scheme.