The Realization and Dectection of Weyl Semimetals and Chiral Anomaly in Cold Atomic Systems

TL;DR

This paper proposes a method to realize and detect Weyl semimetals and chiral anomaly in cold atomic systems using multilayer honeycomb optical lattices with Raman lasers, enabling experimental exploration of topological phases.

Contribution

It introduces a novel approach to create Weyl semimetals in cold atoms via Raman-assisted tunneling in multilayer honeycomb lattices, and suggests detection of Weyl points and chiral anomaly.

Findings

Weyl semimetal phase can be realized with tunable Weyl points.

Landau-Zener tunneling can detect Weyl points.

Chiral anomaly can be observed using magnetic field gradients.

Abstract

In this work, we describe a method to realize 3D Weyl semimetal by coupling multilayers of honeycomb optical lattice in the presence of a pair of Raman lasers. The Raman lasers render each isolated honeycomb layer a Chern insulator. With finite interlayer coupling, the bulk gap of the system closes at certain out-of-plane momenta due to Raman assisted tunnelling and result in the Weyl semimetal phase. Using experimentally relevant parameters, we show that both one and two pairs of Weyl points can be realized by tuning the interlayer coupling strength. We suggest that Landau-Zener tunnelling can be used to detect Weyl points and show that the transition probability increases dramatically when Weyl point emerges. The realization of chiral anomaly by using a magnetic field gradient is also discussed.