Ab initio theory of the N2V defect in diamond for quantum memory implementation

The ${\text{N}}_{2}\mathrm{V}$ defect in diamond is characterized by means of ab initio methods relying on density functional theory calculated parameters of a Hubbard model Hamiltonian. It is shown that this approach appropriately describes the energy levels of correlated excited states induced by this defect. By determining its critical magneto-optical parameters, we propose to realize a long-living quantum memory by ${\text{N}}_{2}\mathrm{V}$ defect, i.e., $H3$ color center in diamond.