Minimizing Backaction through Entangled Measurements

Kang-Da Wu, Elisa Bäumer, Jun-Feng Tang, Karen V. Hovhannisyan, Martí Perarnau-Llobet, Guo-Yong Xiang, Chuan-Feng Li, and Guang-Can Guo
Phys. Rev. Lett. 125, 210401 – Published 16 November 2020
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Abstract

When an observable is measured on an evolving coherent quantum system twice, the first measurement generally alters the statistics of the second one, which is known as measurement backaction. We introduce, and push to its theoretical and experimental limits, a novel method of backaction evasion, whereby entangled collective measurements are performed on several copies of the system. This method is inspired by a similar idea designed for the problem of measuring quantum work [Perarnau-Llobet et al., Phys. Rev. Lett. 118, 070601 (2017)]. By using entanglement as a resource, we show that the backaction can be extremely suppressed compared to all previous schemes. Importantly, the backaction can be eliminated in highly coherent processes.

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  • Received 14 March 2020
  • Accepted 5 October 2020

DOI:https://doi.org/10.1103/PhysRevLett.125.210401

© 2020 American Physical Society

Physics Subject Headings (PhySH)

Quantum Information, Science & TechnologyGeneral Physics

Authors & Affiliations

Kang-Da Wu1,2, Elisa Bäumer3, Jun-Feng Tang1,2, Karen V. Hovhannisyan4,*, Martí Perarnau-Llobet5,†, Guo-Yong Xiang1,2,‡, Chuan-Feng Li1,2, and Guang-Can Guo1,2

  • 1CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, People’s Republic of China
  • 2CAS Center For Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, People’s Republic of China
  • 3Institute for Theoretical Physics, ETH Zurich, 8093 Zürich, Switzerland
  • 4The Abdus Salam International Centre for Theoretical Physics (ICTP), Strada Costiera 11, 34151 Trieste, Italy
  • 5Department of Applied Physics, University of Geneva, 1211 Geneva, Switzerland

  • *Corresponding author. khovhann@ictp.it
  • Corresponding author. marti.perarnaullobet@unige.ch
  • Corresponding author. gyxiang@ustc.edu.cn

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Issue

Vol. 125, Iss. 21 — 20 November 2020

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