Abstract
The interaction of a quantum system with the environment leads to the so-called quantum decoherence. Beyond its fundamental significance, the understanding and the possible control of this dynamics in various scenarios is a key element for mastering quantum information processing. Here we report the quantitative probing of what can be called the quantum decoherence of detectors, a process reminiscent of the decoherence of quantum states in the presence of coupling with a reservoir. We demonstrate how the quantum features of two single-photon counters vanish under the influence of a noisy environment. We thereby experimentally witness the transition between the full-quantum operation of the measurement device to the "semi-classical regime", described by a positive Wigner function. The exact border between these two regimes is explicitely determined and measured experimentally.
- Received 19 May 2011
DOI:https://doi.org/10.1103/PhysRevLett.107.050504
© 2011 American Physical Society
Synopsis
The quantum side of detectors
Published 28 July 2011
By applying environmental noise to a photon detector, researchers have identified the boundary where the device switches from a quantum device to a classical one.
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