Assisted cloning and orthogonal complementing of an unknown state

Abstract

We propose a protocol where one can exploit dual quantum and classical channels to achieve perfect “cloning” and “orthogonal-complementing” of an unknown state with minimal assistance from a state preparer (without revealing what the input state is). The first stage of the protocol requires usual teleportation, and in the second stage the preparer disentangles the leftover entangled states by a single-particle measurement process and communicates a number of classical bits (1-cbit per copy) to different parties so that perfect copies and complement copies are produced. Our protocol produces clones and complement clones of unknown qubit each with a probability 12 and clones of real qubit with unit probability.