Experimental characterization of universal one-way quantum computing

Autor: B A Bell, M S Tame, A S Clark, R W Nock, W J Wadsworth, J G Rarity
Jazyk: angličtina
Rok vydání: 2013
Předmět:
Zdroj: New Journal of Physics, Vol 15, Iss 5, p 053030 (2013)
Druh dokumentu: article
ISSN: 1367-2630
DOI: 10.1088/1367-2630/15/5/053030
Popis: We report the characterization of a universal set of logic gates for one-way quantum computing using a four-photon ‘star’ cluster state generated by fusing photons from two independent photonic crystal fibre sources. We obtain a fidelity for the cluster state of 0.66 ± 0.01 with respect to the ideal case. We perform quantum process tomography to completely characterize a controlled-NOT, Hadamard and T gate all on the same compact entangled resource. Together, these operations make up a universal set of gates such that arbitrary quantum logic can be efficiently constructed from combinations of them. We find process fidelities with respect to the ideal cases of 0.64 ± 0.01 for the CNOT, 0.67 ± 0.03 for the Hadamard and 0.76 ± 0.04 for the T gate. The characterization of these gates enables the simulation of larger protocols and algorithms. As a basic example, we simulate a Swap gate consisting of three concatenated CNOT gates. Our work provides some pragmatic insights into the prospects for building up to a fully scalable and fault-tolerant one-way quantum computer with photons in realistic conditions.
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