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Reply to "Comment on 'Measuring a Photonic Qubit without Destroying It'"

G. J. Pryde·J. L. O'Brien·A. G. White·S. D. Bartlett·T. C. Ralph
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Abstract

In our Letter we proposed a scheme for nondeterministic quantum nondemolition (QND) measurement of the polarization of a single photon--a photonic qubit--using linear optics and photodetection. The scheme works with nonunit probability, but success is heralded by the detection of a single photon in the meter output. We provided an experimental demonstration of this scheme and introduced three universally applicable fidelity measures--the measurement fidelity F_M, the quantum state preparation fidelity F_QSP, and the QND fidelity F_QND--to quantify its performance. The claim of Kok and Munro in their Comment [quant-ph/0406120] is that one of our fidelity measures F_M is not appropriate because it relies on coincidence measurements. We show why this claim is wrong from both a fundamental and an operational perspective.

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G. J. Pryde, J. L. O'Brien, A. G. White, S. D. Bartlett, T. C. Ralph. 2005-07-19. Reply to "Comment on 'Measuring a Photonic Qubit without Destroying It'". https://doi.org/10.1103/physrevlett.95.048902

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