2005/10/31 by Peter van Loock, Kae Nemoto, William J. Munro +2
Computer Science · Physics and Astronomy · #Algorithm #Computer science #Neural Networks and Reservoir Computing #Optics #Physics #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum mechanics #Quantum optics #State (computer science) #Statistical physics #quant-ph
paper · pdf · doi:10.1103/physreva.73.062320
published as Phys. Rev. A 73, 062320 (2006) · final published version
openalex publication_date 2006/06/14 · arxiv created 2006/06/22 · arxiv updated 2016/08/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We discuss the problem of implementing generalized measurements [positive operator-valued measures (POVMs)] with linear optics, either based upon a static linear array or including conditional dynamics. In our approach, a given POVM shall be identified as a solution to an optimization problem for a chosen cost function. We formulate a general principle: the implementation is only possible if a linear-optics circuit exists for which the quantum mechanical optimum (minimum) is still attainable after dephasing the corresponding quantum states. The general principle enables us, for instance, to derive a set of necessary conditions for the linear-optics implementation of the POVM that realizes the quantum mechanically optimal unambiguous discrimination of two pure nonorthogonal states. This extends our previous results on projection measurements and the exact discrimination of orthogonal states.