Ideal Weyl semimetal with 3D spin-orbit coupled ultracold quantum gas

TL;DR

This paper proposes a method to realize the fundamental Weyl semimetal with two Weyl points in ultracold atoms using a 3D spin-orbit coupled optical lattice, and predicts a novel Weyl phase with unique topological features.

Contribution

It demonstrates the first realization of a minimal Weyl semimetal and 3D spin-orbit coupling in ultracold quantum gases, advancing quantum simulation capabilities.

Findings

Realization of a minimal Weyl semimetal with two Weyl points in ultracold atoms.

Prediction of a new Weyl phase with coexisting Weyl points and nodal ring.

Proposed techniques for resolving 3D Weyl band topology experimentally.

Abstract

There is an immense effort in search for various types of Weyl semimetals, of which the most fundamental phase consists of the minimal number of i.e. two Weyl points, but is hard to engineer in solids. Here we demonstrate how such fundamental Weyl semimetal can be realized in a maneuverable optical Raman lattice, with which the three-dimensional (3D) spin-orbit (SO) coupling is synthesised for ultracold atoms. In addition, a new novel Weyl phase with coexisting Weyl nodal points and nodal ring is also predicted here, and is shown to be protected by nontrivial linking numbers. We further propose feasible techniques to precisely resolve 3D Weyl band topology through 2D equilibrium and dynamical measurements. This work leads to the first realization of the most fundamental Weyl semimetal band and the 3D SO coupling for ultracold quantum gases, which are respectively the significant issues in the condensed matter and ultracold atom physics.