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TT: Fachverband Tiefe Temperaturen
TT 84: Fluctuations and Noise
TT 84.4: Talk
Thursday, March 15, 2018, 10:15–10:30, HFT-FT 131
Noninvasive Quantum Measurement of Arbitrary Operator Order by Engineered Non-Markovian Detectors — Johann Bülte1, •Adam Bednorz2, Christoph Bruder3, and Wolfgang Belzig2 — 1Fachbereich Physik, Universität Konstanz, D-78457 Konstanz, Germany — 2Faculty of Physics, University of Warsaw, ul. Pasteura 5, PL02-093 Warsaw, Poland — 3Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
The development of solid-state quantum technologies requires the understanding of quantum measurements in interacting, non-isolated quantum systems. In general, a permanent coupling of detectors to a quantum system leads to memory effects that have to be taken into account in interpreting the measurement results. We analyze a generic setup of two detectors coupled to a quantum system and derive a compact formula in the weak-measurement limit that interpolates between an instantaneous (text-book type) and almost continuous - detector dynamics-dependent - measurement. A quantum memory effect that we term system-mediated detector-detector interaction is crucial to observe non-commuting observables simultaneously. Finally, we propose a mesoscopic double-dot detector setup in which the memory effect is tunable and that can be used to explore the transition to non-Markovian quantum measurements experimentally [arXiv:1711.11347].