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Implementation of projective measurements with linear optics and continuous photon counting

Masahiro Takeoka·Masahide Sasaki·Peter van Loock·Norbert Lütkenhaus
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Abstract

We investigate the possibility of implementing a given projection measurement using linear optics and arbitrarily fast feedforward based on the continuous detection of photons. In particular, we systematically derive the so-called Dolinar scheme that achieves the minimum error discrimination of binary coherent states. Moreover, we show that the Dolinar-type approach can also be applied to projection measurements in the regime of photonic-qubit signals. Our results demonstrate that for implementing a projection measurement with linear optics, in principle, unit success probability may be approached even without the use of expensive entangled auxiliary states, as they are needed in all known (near-)deterministic linear-optics proposals.

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Masahiro Takeoka, Masahide Sasaki, Peter van Loock, Norbert Lütkenhaus. 2005-03-04. Implementation of projective measurements with linear optics and continuous photon counting. https://doi.org/10.1103/physreva.71.022318

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