Hybrid quantum system with nitrogen-vacancy centers in diamond coupled to surface phonon polaritons in piezomagnetic superlattices

We investigate a hybrid quantum system where an ensemble of nitrogen-vacancy (NV) centers in diamond is interfaced with a piezomagnetic superlattice that supports surface phonon polaritons (SPhPs). We show that the strong magnetic coupling between the collective spin waves in the NV spin ensemble and the quantized SPhPs can be realized, thanks to the subwavelength nature of the SPhPs and relatively long spin coherence times. The magnon-polariton coupling allows different modes of the SPhPs to be mapped and orthogonally stored in different spatial modes of excitation in the solid medium. Because of its easy implementation and high tunability, the proposed hybrid structure with NV spins and piezoactive superlattices could be used for quantum memory and quantum computation.