A general approach to physical realization of unambiguous quantum-state discrimination

We present a general scheme to realize the POVMs for the unambiguous discrimination of quantum states. For any set of pure states it enables us to set up a feasible linear optical circuit to perform their optimal discrimination, if they are prepared as single-photon states. An example of unknown states discrimination is discussed as the illustration of the general scheme. (c) 2006 Elsevier B.V. All rights reserved.