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Implementation of generalized quantum measurements for unambiguous discrimination of multiple nonorthogonal coherent states



Francisco E. Becerra Chavez, Jingyun Fan, Alan L. Migdall


Generalized quantum measurements can perform perfect discrimination of nonorthogonal states by allowing for inconclusive results, task which is impossible performing only measurements with definite outcomes. We demonstrate the realization of generalized quantum measurements for unambiguous discrimination of four nonorthogonal coherent states and obtain its quantum mechanical description, its positive-operator valued measurements (POVMs). For practical realizations of these POVMs, where noise and realistic imperfections prevent perfect unambiguous discrimination, we show that our experiential implementation outperforms any ideal measurement with standardquantum- limited performance implementing the same nonideal unambiguous state discrimination task for low mean photon numbers.
Nature Communications


Quantum communications, standard quantum limit, quantum measurements, coherent states, quantum information, state discrimination
Created June 18, 2013, Updated November 10, 2018