Quantum communication with SU(2) invariant separable 2 x N level systems

Information is encoded in a qubit in the form of its Bloch vector. In this paper, we propose protocols for remote transfers of information in a known and an unknown qubit to qudits using SU(2)-invariant 2 x N-level separable discordant states as quantum channels. These states have been identified as separable equivalents of the two-qubit entangled Werner states in Bharath and Ravishankar (Phys Rev A 89:062110, 2014). Due to SU(2) x SU(2) invariance of these states, the remote qudit can be changed by performing appropriate measurements on the qubit. We also propose a protocol for transferring information of a family of unknown qudits to remote qudits using 2 x N-level states as channels. Finally, we propose a protocol for swapping of quantum discord from 2 x N-level systems to N x N-level systems. All the protocols proposed in this paper involve separable states as quantum channels.