Quantum Edge Detection

Santiago Llorens; Walther González; Gael Sentís; John Calsamiglia; Ramon Muñoz-Tapia; Emili Bagan

doi:10.22331/q-2025-04-03-1687

Quantum Edge Detection

Santiago Llorens¹, Walther González^1,2, Gael Sentís^1,3, John Calsamiglia¹, Ramon Muñoz-Tapia¹, and Emili Bagan¹

¹Física Teòrica: Informació i Fenòmens Quàntics, Departament de Física, Universitat Autònoma de Barcelona (UAB), 08193 Bellaterra (Barcelona), Spain
²Grupo de Óptica Cuántica, Departamento de Física, Universidad de los Andes, Cra. 1, 18A-12, Bogotá, Colombia
³Ideaded, Carrer de la Tecnologia, 35, 08840 Viladecans, Barcelona, Spain

Published:	2025-04-03, volume 9, page 1687
Editor:	Vedran Dunjko
Eprint:	arXiv:2405.11373v3
Doi:	https://doi.org/10.22331/q-2025-04-03-1687
Citation:	Quantum 9, 1687 (2025).

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Abstract

This paper introduces quantum edge detection, aimed at locating boundaries of quantum domains where all particles share the same pure state. Focusing on the 1D scenario of a string of particles, we develop an optimal protocol for quantum edge detection, efficiently computing its success probability through Schur-Weyl duality and semidefinite programming techniques. We analyze the behavior of the success probability as a function of the string length and local dimension, with emphasis in the limit of long strings. We present a protocol based on square root measurement, which proves asymptotically optimal. Additionally, we explore a mixed quantum change point detection scenario where the state of particles transitions from known to unknown, which may find practical applications in detecting malfunctions in quantum devices

Featured image: Illustration of a qubit array divided into two domains. Quantum edge detection aims to identify the boundary (highlighted in green) separating them.

► BibTeX data

@article{Llorens2025quantumedge,
  doi = {10.22331/q-2025-04-03-1687},
  url = {https://doi.org/10.22331/q-2025-04-03-1687},
  title = {Quantum {E}dge {D}etection},
  author = {Llorens, Santiago and Gonz{\'{a}}lez, Walther and Sent{\'{i}}s, Gael and Calsamiglia, John and Mu{\~{n}}oz-Tapia, Ramon and Bagan, Emili},
  journal = {{Quantum}},
  issn = {2521-327X},
  publisher = {{Verein zur F{\"{o}}rderung des Open Access Publizierens in den Quantenwissenschaften}},
  volume = {9},
  pages = {1687},
  month = apr,
  year = {2025}
}

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