Online strategies for exactly identifying a quantum change point

Gael Sentís, Esteban Martínez-Vargas, and Ramon Muñoz-Tapia
Phys. Rev. A 98, 052305 – Published 5 November 2018

Abstract

We consider online detection strategies for identifying a change point in a stream of quantum particles allegedly prepared in identical states. We show that the identification of the change point can be done without error via sequential local measurements while attaining the optimal performance bound set by quantum mechanics. In this way, we establish the task of exactly identifying a quantum change point as an instance where local protocols are as powerful as global ones. The optimal online detection strategy requires only one bit of memory between subsequent measurements, and it is amenable to experimental realization with current technology.

  • Figure
  • Received 30 January 2018
  • Corrected 29 November 2018

DOI:https://doi.org/10.1103/PhysRevA.98.052305

©2018 American Physical Society

Physics Subject Headings (PhySH)

Quantum Information, Science & Technology

Corrections

29 November 2018

Correction: Equation (B2) was improperly manipulated during the final production stage and has been fixed.

Authors & Affiliations

Gael Sentís1,*, Esteban Martínez-Vargas2,†, and Ramon Muñoz-Tapia2,‡

  • 1Naturwissenschaftlich-Technische Fakultät, Universität Siegen, 57068 Siegen, Germany
  • 2Física Teòrica: Informació i Fenòmens Quàntics, Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Spain

  • *gael.sentis@uni-siegen.de
  • esteban.martinez@uab.cat
  • ramon.munoz@uab.cat

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Issue

Vol. 98, Iss. 5 — November 2018

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