Selective coherent spin transportation in a spin-orbit-coupled bosonic junction

We propose a theoretical scheme for realizing selective coherent spin transportation in a spin-orbit-coupled bosonic gas trapped in a symmetric double well by fast modulation of the energy-level unbalance between the two wells. The modulation can be tuned in such a way that an arbitrarily, a priori prescribed spin type (single spin or a spin pair with opposite spins) and the number of these spin bosons with or without spin flipping are allowed to tunnel. Furthermore, prescribed superexchange of spin bosons (where only pure spin exchange is allowed between the two wells and the atom number in each well is not changed) is also presented. The resonance conditions of realizing this selective coherent spin transportation are obtained analytically and confirmed numerically. This engineering provides a possible means for spin control and accurate counting or efficient filtering of the number of spins.