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Publication - Dr Anthony Laing

    Universal linear optics


    Carolan, J, Harrold, C, Sparrow, C, Lopez, EM, Russell, N, Silverstone, J, Shadbolt, P, Matsuda, N, Ogama, M, Itoh, M, Marshall, G, Thompson, M, Matthews, J, Hashimoto, T, O'Brien, J & Laing, A, 2015, ‘Universal linear optics’. Science, vol 349., pp. 711-716


    Linear optics underpins fundamental tests of quantum mechanics and quantum technologies. We demonstrate a single reprogrammable optical circuit that is sufficient to implement all possible linear optical protocols up to the size of that circuit. Our six-mode universal system consists of a cascade of 15 Mach-Zehnder interferometers with 30 thermo-optic phase shifters integrated into a single photonic chip that is electrically and optically interfaced for arbitrary setting of all phase shifters, input of up to six photons, and their measurement with a 12-single-photon detector system. We programmed this system to implement heralded quantum logic and entangling gates, boson sampling with verification tests, and six-dimensional complex Hadamards. We implemented 100 Haar random unitaries with an average fidelity of 0.999 ± 0.001. Our system can be rapidly reprogrammed to implement these and any other linear optical protocol, pointing the way to applications across fundamental science and quantum technologies.

    Full details in the University publications repository