Dynamical Weyl Points and 4D Nodal Rings in Cold Atomic Gases

TL;DR

This paper demonstrates the theoretical prediction and experimental feasibility of dynamical Weyl points and 4D Weyl nodal rings in cold atomic gases, revealing tunable topological pumps beyond quantized values.

Contribution

It introduces the concept of dynamical Weyl points and 4D nodal rings protected by Chern numbers in cold atoms, and proposes an experimental scheme to observe tunable topological pumping.

Findings

Dynamical Weyl points and 4D Weyl nodal rings emerge in cold atomic systems.

Topological pump occurs but with non-quantized, tunable particle transfer.

Experimental scheme proposed for realization and observation.

Abstract

Controllability of ultracold atomic gases has reached an unprecedented level, allowing for experimental realization of the long-sought-after Thouless pump, which can be interpreted as a dynamical quantum Hall effect. On the other hand, Weyl semimetals and Weyl nodal line semimetals with touching points and rings in band structures have sparked tremendous interest in various fields in the past few years. Here, we show that dynamical Weyl points and dynamical 4D Weyl nodal rings, which are protected by the first Chern number on a parameter surface formed by quasi-momentum and time, emerge in a two-dimensional and three-dimensional system, respectively. We find that the topological pump occurs in these systems but the amount of pumped particles is not quantized and can be continuously tuned by controlling experimental parameters over a wide range. We also propose an experimental scheme to realize the dynamical Weyl points and 4D Weyl nodal rings and to observe their corresponding topological pump in cold atomic gases.