Efficient quantum computing using coherent photon conversion

Langford, N. K., Ramelow, S., Prevedel, R., Munro, W. J., Milburn, G. J. and Zeilinger, A. (2011) Efficient quantum computing using coherent photon conversion. Nature, 478 7369: 360-363. doi:10.1038/nature10463

Author Langford, N. K.
Ramelow, S.
Prevedel, R.
Munro, W. J.
Milburn, G. J.
Zeilinger, A.
Title Efficient quantum computing using coherent photon conversion
Journal name Nature   Check publisher's open access policy
ISSN 0028-0836
Publication date 2011-10-01
Year available 2011
Sub-type Letter to editor, brief commentary or brief communication
DOI 10.1038/nature10463
Open Access Status Not yet assessed
Volume 478
Issue 7369
Start page 360
End page 363
Total pages 4
Place of publication London, United Kingdom
Publisher Nature Publishing Group
Language eng
Subject 2700 Medicine
1000 General
Abstract Single photons are excellent quantum information carriers: they were used in the earliest demonstrations of entanglement(1) and in the production of the highest-quality entanglement reported so far(2,3). However, current schemes for preparing, processing and measuring them are inefficient. For example, down-conversion provides heralded, but randomly timed, single photons(4), and linear optics gates are inherently probabilistic(5). Here we introduce a deterministic process-coherent photon conversion (CPC)-that provides a new way to generate and process complex, multiquanta states for photonic quantum information applications. The technique uses classically pumped nonlinearities to induce coherent oscillations between orthogonal states of multiple quantum excitations. One example of CPC, based on a pumped four-wave-mixing interaction, is shown to yield a single, versatile process that provides a full set of photonic quantum processing tools. This set satisfies the DiVincenzo criteria for a scalable quantum computing architecture(6), including deterministic multiqubit entanglement gates (based on a novel form of photon-photon interaction), high-quality heralded single-and multiphoton states free from higher-order imperfections, and robust, high-efficiency detection. It can also be used to produce heralded multiphoton entanglement, create optically switchable quantum circuits and implement an improved form of down-conversion with reduced higher-order effects. Such tools are valuable building blocks for many quantum-enabled technologies. Finally, using photonic crystal fibres we experimentally demonstrate quantum correlations arising from a four-colour nonlinear process suitable for CPC and use these measurements to study the feasibility of reaching the deterministic regime with current technology(4,7). Our scheme, which is based on interacting bosonic fields, is not restricted to optical systems but could also be implemented in optomechanical, electromechanical and superconducting systems(8-12) with extremely strong intrinsic nonlinearities. Furthermore, exploiting higher-order nonlinearities with multiple pump fields yields a mechanism for multiparty mediation of the complex, coherent dynamics.
Keyword Linear Optics
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Letter to editor, brief commentary or brief communication
Collections: School of Mathematics and Physics
Official 2012 Collection
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Citation counts: TR Web of Science Citation Count  Cited 60 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 70 times in Scopus Article | Citations
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