2002/09/30 by Andrew M. Childs, Richard Cleve, E. Deotto +4 · 99 citations
Computer Science · Physics and Astronomy · #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum-Dot Cellular Automata #quant-ph
paper · pdf · doi:10.1145/780542.780552
published as Proc. 35th ACM Symposium on Theory of Computing (STOC 2003), pp. 59-68 · 24 pages, 7 figures; minor corrections and clarifications
arxiv created 2002/10/25 · openalex publication_date 2003/06/09 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/29
We construct a black box graph traversal problem that can be solved exponentially faster on a quantum computer than on a classical computer. The quantum algorithm is based on a continuous time quantum walk, and thus employs a different technique from previous quantum algorithms based on quantum Fourier transforms. We show how to implement the quantum walk efficiently in our black box setting. We then show how this quantum walk solves our problem by rapidly traversing a graph. Finally, we prove that no classical algorithm can solve the problem in subexponential time.