FAITHFUL CLONE OF AN UNKNOWN TWO-PARTICLE ENTANGLED STATE WITH ASSISTANCE
Song-Ya Ma, Xiu‐Bo Chen, Ming‐Xing Luo, Xinxin Niu, Yixian Yang · International Journal of Quantum Information · 2010
We propose a deterministic and faithful scheme for realizing the assisted clone of an unknown two-particle entangled state. The first stage of the protocol requires teleportation via maximal entanglement. In the second stage, a novel set of mutually orthogonal basis vectors is constructed. With the assistance of the preparer through a two-particle projective measurement under this basis, a perfect copy of an original state can be produced. Compared with the previous protocols which produce the unknown state and its orthogonal complement state at the site of the sender, our scheme generates the unknown state deterministically. On the other hand, we put forward another assisted clone scheme via nonmaximal entanglement as the quantum channel. A faithful copy of the unknown state can be obtained with a certain probability.