Excitation of knotted vortex lines in matter waves

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.