Year: 2015
Type: article
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.
Source: Nature Communications
DOI: 10.1038/ncomms8913
Language: English
Subfield: Artificial Intelligence
Field: Computer Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,788
Funders: John Templeton Foundation, Foundational Questions Institute, European Commission, Vienna Science and Technology Fund, Austrian Science Fund, Consejo Nacional de Ciencia y Tecnología, U.S. Air Force, Natural Sciences and Engineering Research Council of Canada, Air Force Office of Scientific Research
Awards: GRAPHENE-BASED SINGLE-PHOTON NONLINEAR OPTICAL DEVICES, Emulators of Quantum Frustrated Magnetism, Randomness and Quantum Entanglement, G2503264296, G2768210732, Quantum Simulation on a Photonic Chip, G4344566021, Quantum Integrated Light Matter Interface, Photonic Integrated Compound Quantum Encoding, Photonic Quantum Simulations, PhoCluDi - Photonic Cluster States From Diamond
OpenAlex ID: W1615134144