Discriminating 16 mutually orthogonal 4-atom cluster states via cavity QED in teleporting arbitrary unknown two-atom state with a 4-atom cluster state as quantum channel

We propose a scheme for discriminating 16 mutually orthogonal 4-atom cluster entangled states (CES) via cavity QED in teleporting an arbitrary unknown two-atom state with a 4-atom CES as quantum channel. Utilizing the interaction of atoms with cavity and classical field, the complicated 4-atom CESs are transformed into the simple 4-atom product states. Hence the difficulty of measurement during the teleportation process is degraded. In the present scheme, we allow for the case of a strong classical driving field and the detuning between the atoms and the cavity is assumed large enough. Thereby the photon- number- dependent parts in the effective Hamiltonian can be neglected, and the scheme is insensitive to both the cavity decay and the thermal field.