Measurement-induced population switching

Quantum information processing is a key technology in the ongoing second quantum revolution, with a wide variety of hardware platforms competing toward its realization. An indispensable component of such hardware is a measurement device, i.e., a quantum detector that is used to determine the outcome...

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Main Authors: Michael S. Ferguson, Leon C. Camenzind, Clemens Müller, Daniel E. F. Biesinger, Christian P. Scheller, Bernd Braunecker, Dominik M. Zumbühl, Oded Zilberberg
Format: Article
Language:English
Published: American Physical Society 2023-04-01
Series:Physical Review Research
Online Access:http://doi.org/10.1103/PhysRevResearch.5.023028
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author Michael S. Ferguson
Leon C. Camenzind
Clemens Müller
Daniel E. F. Biesinger
Christian P. Scheller
Bernd Braunecker
Dominik M. Zumbühl
Oded Zilberberg
author_facet Michael S. Ferguson
Leon C. Camenzind
Clemens Müller
Daniel E. F. Biesinger
Christian P. Scheller
Bernd Braunecker
Dominik M. Zumbühl
Oded Zilberberg
author_sort Michael S. Ferguson
collection DOAJ
description Quantum information processing is a key technology in the ongoing second quantum revolution, with a wide variety of hardware platforms competing toward its realization. An indispensable component of such hardware is a measurement device, i.e., a quantum detector that is used to determine the outcome of a computation. The act of measurement in quantum mechanics, however, is naturally invasive as the measurement apparatus becomes entangled with the system that it observes. This always leads to a disturbance in the observed system, a phenomenon called quantum measurement backaction, which should solely lead to the collapse of the quantum wave function and the physical realization of the measurement postulate of quantum mechanics. Here we demonstrate that backaction can fundamentally change the quantum system through the detection process. For quantum information processing, this means that the readout alters the system in such a way that a faulty measurement outcome is obtained. Specifically, we report a backaction-induced population switching, where the bare presence of weak, nonprojective measurements by an adjacent charge sensor inverts the electronic charge configuration of a semiconductor double quantum dot system. The transition region grows with measurement strength and is suppressed by temperature, in excellent agreement with our coherent quantum backaction model. Our result exposes backaction channels that appear at the interplay between the detector and the system environments, and opens new avenues for controlling and mitigating backaction effects in future quantum technologies.
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spelling doaj.art-b8b332cdbbf0432cae011cff735fccff2024-04-12T17:30:10ZengAmerican Physical SocietyPhysical Review Research2643-15642023-04-015202302810.1103/PhysRevResearch.5.023028Measurement-induced population switchingMichael S. FergusonLeon C. CamenzindClemens MüllerDaniel E. F. BiesingerChristian P. SchellerBernd BrauneckerDominik M. ZumbühlOded ZilberbergQuantum information processing is a key technology in the ongoing second quantum revolution, with a wide variety of hardware platforms competing toward its realization. An indispensable component of such hardware is a measurement device, i.e., a quantum detector that is used to determine the outcome of a computation. The act of measurement in quantum mechanics, however, is naturally invasive as the measurement apparatus becomes entangled with the system that it observes. This always leads to a disturbance in the observed system, a phenomenon called quantum measurement backaction, which should solely lead to the collapse of the quantum wave function and the physical realization of the measurement postulate of quantum mechanics. Here we demonstrate that backaction can fundamentally change the quantum system through the detection process. For quantum information processing, this means that the readout alters the system in such a way that a faulty measurement outcome is obtained. Specifically, we report a backaction-induced population switching, where the bare presence of weak, nonprojective measurements by an adjacent charge sensor inverts the electronic charge configuration of a semiconductor double quantum dot system. The transition region grows with measurement strength and is suppressed by temperature, in excellent agreement with our coherent quantum backaction model. Our result exposes backaction channels that appear at the interplay between the detector and the system environments, and opens new avenues for controlling and mitigating backaction effects in future quantum technologies.http://doi.org/10.1103/PhysRevResearch.5.023028
spellingShingle Michael S. Ferguson
Leon C. Camenzind
Clemens Müller
Daniel E. F. Biesinger
Christian P. Scheller
Bernd Braunecker
Dominik M. Zumbühl
Oded Zilberberg
Measurement-induced population switching
Physical Review Research
title Measurement-induced population switching
title_full Measurement-induced population switching
title_fullStr Measurement-induced population switching
title_full_unstemmed Measurement-induced population switching
title_short Measurement-induced population switching
title_sort measurement induced population switching
url http://doi.org/10.1103/PhysRevResearch.5.023028
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