Preservation of entanglement in a two-qubit-spin coupled system

A theoretical scheme for preserving the entanglement in a two-qubit-spin coupled system in the presence of Dzyaloshinskii–Moriya (DM) anisotropic antisymmetric interaction is proposed. On the basis of a sequence of operations performed periodically on the system, the scheme can preserve the entanglement of the system starting from any initial state with any desired high precision for any desired long duration.

► A theoretical scheme for preserving the entanglement in a two-spin system is proposed.
► This scheme can work for any initial state, with any desired high precision, for any desired long duration.
► We show the effect of this scheme by giving an example.