Quadratic speedup for finding marked vertices by quantum walks

Authors
Publication date 2020
Host editors
  • K. Makarychev
  • Y. Makarychev
  • M. Tulsiani
  • G. Kamath
  • J. Chuzhoy
Book title STOC '20
Book subtitle proceedings of the 52nd Annual ACM SIGACT Symposium on Theory of Computing : June 22-26, 2020, Chicago, IL, USA
ISBN (electronic)
  • 9781450369794
Event 52nd Annual ACM SIGACT Symposium on Theory of Computing, STOC 2020
Pages (from-to) 412-424
Number of pages 13
Publisher New York, NY: Association for Computing Machinery
Organisations
  • Interfacultary Research - Institute for Logic, Language and Computation (ILLC)
Abstract

A quantum walk algorithm can detect the presence of a marked vertex on a graph quadratically faster than the corresponding random walk algorithm (Szegedy, FOCS 2004). However, quantum algorithms that actually find a marked element quadratically faster than a classical random walk were only known for the special case when the marked set consists of just a single vertex, or in the case of some specific graphs. We present a new quantum algorithm for finding a marked vertex in any graph, with any set of marked vertices, that is (up to a log factor) quadratically faster than the corresponding classical random walk, resolving a question that had been open for 15 years.

Document type Conference contribution
Language English
Published at https://doi.org/10.1145/3357713.3384252
Other links https://www.scopus.com/pages/publications/85086756521
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