Rabi Switch of Condensate Wavefunctions in a Spinor Bose Gas.

Using a time-dependent linear (Rabi) coupling between the components of a weakly interacting multicomponent Bose-Einstein condensate (BEC), we propose a protocol for transferring the wavefunction of one component to the other. This “Rabi switch” can be generated in a binary BEC mixture by an electromagnetic field between the two components, typically two hyperfine states. When the wavefunction to be transfered is - at a given time - a stationary state of the multicomponent Hamiltonian, then, after a time delay (depending on the Rabi frequency), it is possible to have the same wavefunction on the other condensate. The Rabi switch can be used to transfer also moving bright matter-wave solitons, as well as vortices and vortex lattices in two-dimensional condensates. The efficiency of the proposed switch is shown to be 100 % when inter-species and intra-species interaction strengths are equal. The deviations from equal interaction strengths are analyzed within a two-mode model and the dependence of the efficiency on the interaction strengths and on the presence of external potentials is examined in both 1D and 2D settings.