Experimental superposition of orders of quantum gates

Autor(en)

Lorenzo M. Procopio, Amir Moqanaki, Mateus Araujo, Fabio Costa, Irati Alonso Calafell, Emma G. Dowd, Deny R. Hamel, Lee A. Rozema, Caslav Brukner, Philip Walther

Abstrakt

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.

Organisation(en)

Quantenoptik, Quantennanophysik und Quanteninformation

Externe Organisation(en)

Österreichische Akademie der Wissenschaften (ÖAW), Universität Wien

Journal

Nature Communications

Band

6

Anzahl der Seiten

6

ISSN

2041-1723

Publikationsdatum

08-2015

Peer-reviewed

Ja

ÖFOS 2012

103025 Quantenmechanik

Schlagwörter

ASJC Scopus Sachgebiete

Allgemeine Physik und Astronomie, Allgemeine Chemie, Allgemeine Biochemie, Genetik und Molekularbiologie

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/7aa6af36-b623-46c1-8ced-63936f488659