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SUMMARY:Shintaro Minagawa: Quantum channel incompatibility: A fundamental 
 principle constraining quantum communication and quantum measurement
DTSTART:20261103T093000Z
DTEND:20261103T103000Z
DTSTAMP:20261112T103800Z
UID:indico-event-17544@indico.math.cnrs.fr
DESCRIPTION:A quantum channel is a mathematical description of the evoluti
 on or processing of a quantum system. Sometimes\, multiple quantum channel
 s cannot be realized simultaneously as parts of a single joint channel\; t
 his phenomenon is known as quantum channel incompatibility [1]. Quantum ch
 annel incompatibility provides a unified perspective on various phenomena\
 , such as the no-broadcasting theorem [2] in quantum communication and the
  unavoidable disturbance that occurs when extracting information through q
 uantum measurements [3]. In this talk\, moving beyond such qualitative no-
 go theorems\, we address the question of the minimum total error incurred 
 when attempting to jointly realize incompatible quantum channels. We show 
 that the minimum total error is bounded from above and below in terms of t
 he generalized robustness of incompatibility\, a measure of channel incomp
 atibility that can be computed via convex optimization. By applying this r
 esult to quantum measurements\, we also derive a universal tradeoff betwee
 n the informativeness of a quantum measurement\, measurement error\, and t
 he resulting disturbance. This talk is based on our work [4]. \n[1] T. He
 inosaari and T. Miyadera\, J. Phys. A: Math. Theor. 50\, 135302 (2017).[2]
  H. Barnum\, C. M. Caves\, C. A. Fuchs\, R. Jozsa\, and B. Schumacher\, Ph
 ys. Rev. Lett. 76\, 2818 (1996).[3] P. Busch\, “No Information Without D
 isturbance”: Quantum Limitations of Measurement. In: Quantum Reality\, R
 elativistic Causality\, and Closing the Epistemic Circle. The Western Onta
 rio Series in Philosophy of Science\, vol 73. Springer\, Dordrecht (2009).
 [4] S. Minagawa\, R. Takakura\, and K. Torii\, arXiv:2605.11924 (2026).\n\
 nhttps://indico.math.cnrs.fr/event/17544/
URL:https://indico.math.cnrs.fr/event/17544/
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