Chiral magnetic effect in three-dimensional optical lattices

TL;DR

This paper proposes an experimental scheme using ultracold atoms in 3D optical lattices to observe the chiral magnetic effect, a topological current associated with Weyl semimetals, which has been elusive in experiments.

Contribution

It introduces a feasible method to realize and detect the CME in an artificial Weyl semimetal using ultracold atoms with tunable spin-orbital coupling and laser-assisted tunneling.

Findings

Design of a system with paired Weyl points exhibiting dipolar chiral anomaly

Implementation of artificial magnetic fields to induce topological currents

Proposal for measuring CME via center-of-mass motion of ultracold atoms

Abstract

Although Weyl semimetals have been extensively studied for exploring rich topological physics, the direct observation of the celebrated chiral magnetic effect (CME) associated with the so-called dipolar chiral anomaly has long intrigued and challenged physicists, still remaining elusive in nature. Here we propose a feasible scheme for experimental implementation of ultracold atoms that may enable us to probe the CME with a pure topological current in an artificial Weyl semimetal. The paired Weyl points with the dipolar chiral anomaly emerge in the presence of the well-designed spin-orbital coupling and laser-assisted tunneling. Both of the two artificial fields are readily realizable and highly tunable via current optical techniques using ultracold atoms trapped in three-dimensional optical lattices, providing a reliable way for manipulating Weyl points in the momentum-energy space. By applying a weak artificial magnetic field, the system processes an auxiliary current originated from the topology of a paired Weyl points, namely, the pure CME current. This topological current can be extracted from measuring the center-of-mass motion of ultracold atoms, which may pave the way to directly and unambiguously observe the CME in experiments.