Macroscopic superposition of vortex states in a matter wave

TL;DR

This paper reports the experimental creation of macroscopic vortex superpositions in ultracold gases, demonstrating controllability and long coherence times, advancing quantum information processing capabilities.

Contribution

It introduces a method to generate and control high-dimensional vortex superpositions in matter waves using Raman coupling, with significantly extended coherence times.

Findings

Successful creation of two- and three-vortex superpositions

Superpositions are controllable on the Bloch sphere

Lifetime of superpositions is approximately 25 ms

Abstract

Generating the vortex-state superposition in a matter wave is demanded in many quantum processes such as quantum memory and quantum metrology. Here we report the experimental generation of macroscopic superposition of vortex states in ultracold quantum gases. By transferring an optical vortex-state superposition to the center-of-mass rotational state of ultracold atoms using the Raman coupling technique, we realize two-vortex and three-vortex superposition states in quantum gases, demonstrating the high dimensionality of the vortex state. We show the controllability of the superposition states on the Bloch sphere. The lifetime of the vortex superposition state in quantum gases is as large as 25 ms, about two orders of magnitude longer than the storage time in atomic ensembles. This work paves the way for high dimensional quantum processing in matter waves.