Continuous quantum measurement with independent detector cross-correlations

Abstract

We investigate the advantages of using two independent, linear detectors for continuous quantum measurement. For single-shot quantum measurement, the measurement is maximally efficient if the detectors are twins. For weak continuous measurement, cross-correlations allow a violation of the Korotkov-Averin bound for the detector's signal-to-noise ratio. A vanishing noise background provides a nontrivial test of ideal independent quantum detectors. We further investigate the correlations of non-commuting operators, and consider possible deviations from the independent detector model for mesoscopic conductors coupled by the screened Coulomb interaction.

4 pages, 2 figures

References in corpus (3)

• Quantum-Limited Position Detection and Amplification: A Linear Response Perspective
• Quantum Nondemolition Measurement of a Kicked Qubit
• Output spectrum of a measuring device at arbitrary voltage and temperature