Excitation of knotted vortex lines in matter waves

TL;DR

This paper demonstrates a method to create and study knotted vortex lines in Bose-Einstein condensates using coherent two-photon Raman transitions, enabling complex topological structures in matter waves.

Contribution

It introduces a novel technique for imprinting knotted vortex lines into matter waves via Raman transitions, expanding control over topological excitations in ultracold gases.

Findings

Successful imprinting of knotted vortex lines in BECs.

Analysis of the dynamics of knotted vortex structures.

Discussion on experimental feasibility of the method.

Abstract

We study the creation of knotted ultracold matter waves in Bose-Einstein condensates via coherent two-photon Raman transitions with a $\Lambda$ level configuration. The Raman transition allows an indirect transfer of atoms from the internal state $\left| a \right\rangle$ to the target state $\left| b \right\rangle$ via an excited state $\left| e \right\rangle$, that would be otherwise dipole-forbidden. This setup enables us to imprint three-dimensional knotted vortex lines embedded in the the probe field to the density in the target state. We elaborate on experimental feasibility as well as on subsequent dynamics of the matter wave.