Arbitrary coherent superpositions of quantized vortices in Bose-Einstein condensates via orbital angular momentum of light

We recently proposed a scheme for the creation of coherent superpositions of vortex states in Bose-Einstein condensates (BECs) using orbital angular momentum (OAM) states of light [ Phys. Rev. Lett. 95 173601 (2005)]. Here we discuss further technical details of the proposal, provide an alternative, time-reversal-symmetric scheme for transfer of a superposition of OAM states of light to the BEC via a procedure analogous to the traditional stimulated Raman adiabatic passage technique, and discuss an alternative trap configuration conducive for sustaining large charge vortices. Superpositions of OAM states of light, that can be created using the existing experimental techniques, can be transferred to an initially nonrotating BEC via a specially devised Raman coupling scheme. The techniques proposed here open up avenues to study coherent interaction of OAM states of light with matter. The study could also be employed for performing various quantum-information-processing tasks with OAM states of light—including a memory for a quantum state of the initial superposition.