Better schemes for quantum interrogation in lossy experiments.
We show that several schemes exist for improving the efficiency of quantum interrogations (or "interaction-free" measurements), which in principle are limited by lossy experimental components. We show how one new scheme (the "Helstrom" scheme) can efficiently detect the presence of a bomb which has been designed to foil standard quantum interrogations by arming itself when there is high probability of a photon being in the region. This particular new scheme can probe a region of space with a greater probability of success than a person in that region determining they are being probed.
Rudolph
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Department of Physics, University of Toronto, Toronto, Canada M5S 1A7.