Quantum interference enables constant-time quantum information processing

M. Stobińska*, A. Buraczewski, M. Moore, W. R. Clements, Jelmer Jan Renema, S.W. Nam, T. Gerrits, A. Lita, W. S. Kolthammer, Andreas Eckstein, Ian A. Walmsley

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

13 Citations (Scopus)
91 Downloads (Pure)


It is an open question how fast information processing can be performed and whether quantum effects can speed up the best existing solutions. Signal extraction, analysis, and compression in diagnostics, astronomy, chemistry, and broadcasting build on the discrete Fourier transform. It is implemented with the fast Fourier transform (FFT) algorithm that assumes a periodic input of specific lengths, which rarely holds true. A lesser-known transform, the Kravchuk-Fourier (KT), allows one to operate on finite strings of arbitrary length. It is of high demand in digital image processing and computer vision but features a prohibitive runtime. Here, we report a one-step computation of a fractional quantum KT. The quantum d-nary (qudit) architecture we use comprises only one gate and offers processing time independent of the input size. The gate may use a multiphoton Hong-Ou-Mandel effect. Existing quantum technologies may scale it up toward diverse applications.
Original languageEnglish
Article numbereaau9674
JournalScience advances
Issue number7
Publication statusPublished - 19 Jul 2019


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