Experimental superposition of orders of quantum gates

Procopio, Lorenzo M., Moqanaki, Amir, Araujo, Mateus, Costa, Fabio, Calafell, Irati A., Dowd, Emma G., Hamel, Dendy R., Rozema, Lee A., Brukner, Caslav and Walther, Philip (2015) Experimental superposition of orders of quantum gates. Nature Communications, 6 7913: 1-6. doi:10.1038/ncomms8913

Author Procopio, Lorenzo M.
Moqanaki, Amir
Araujo, Mateus
Costa, Fabio
Calafell, Irati A.
Dowd, Emma G.
Hamel, Dendy R.
Rozema, Lee A.
Brukner, Caslav
Walther, Philip
Title Experimental superposition of orders of quantum gates
Journal name Nature Communications   Check publisher's open access policy
ISSN 2041-1723
Publication date 2015-08-07
Year available 2015
Sub-type Article (original research)
DOI 10.1038/ncomms8913
Open Access Status DOI
Volume 6
Issue 7913
Start page 1
End page 6
Total pages 6
Place of publication London, United Kingdom
Publisher Nature Publishing Group
Language eng
Subject 1600 Chemistry
1300 Biochemistry, Genetics and Molecular Biology
3100 Physics and Astronomy
Abstract Quantum computers achieve a speed-up by placing quantum bits (qubits) in superpositions of different states. However, it has recently been appreciated that quantum mechanics also allows one to ‘superimpose different operations’. Furthermore, it has been shown that using a qubit to coherently control the gate order allows one to accomplish a task—determining if two gates commute or anti-commute—with fewer gate uses than any known quantum algorithm. Here we experimentally demonstrate this advantage, in a photonic context, using a second qubit to control the order in which two gates are applied to a first qubit. We create the required superposition of gate orders by using additional degrees of freedom of the photons encoding our qubits. The new resource we exploit can be interpreted as a superposition of causal orders, and could allow quantum algorithms to be implemented with an efficiency unlikely to be achieved on a fixed-gate-order quantum computer.
Keyword Multidisciplinary Sciences
Science & Technology - Other Topics
Q-Index Code C1
Q-Index Status Provisional Code
Grant ID 295293
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Mathematics and Physics
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Citation counts: TR Web of Science Citation Count  Cited 37 times in Thomson Reuters Web of Science Article | Citations
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