Experimental investigation of an eight-qubit unit cell in a superconducting optimization processor

By R. Harris, M. Johnson, T. Lanting, A. Berkley, J. Johansson, P. Bunyk, E. Tolkacheva, E. Ladizinsky, N. Ladizinsky, T. Oh and 16 more. 2010

231 citations recorded by the source corpus.

A superconducting chip containing a regular array of flux qubits, tunable interqubit inductive couplers, an XY-addressable readout system, on-chip programmable magnetic memory, and a sparse network of analog control lines has been studied. The architecture of the chip and the infrastructure used to control it were designed to facilitate the implementation of an adiabatic quantum optimization algorithm. The performance of an eight-qubit unit cell on this chip has been characterized by measuring its success in solving a large set of random Ising spin-glass problem instances as a function of temperature. The experimental data are consistent with the predictions of a quantum mechanical model of an eight-qubit system coupled to a thermal environment. These results highlight many of the key practical challenges that we have overcome and those that lie ahead in the quest to realize a functional large-scale adiabatic quantum information processor.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/de8e16a4a4225e8f8be7b43cc5a8bcfa8c1d4b4e

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Citations in the corpus

Quantum Simulation (2013, background): “As for scalability, circuits containing 512 qubits have been fabricated (Harris, 2012; Harris et al., 2010), although quantum coherence was not tested on these circuits in the same way that coherence is commonly tested in other experiments using small numbers of qubits.”
Evidence for quantum annealing with more than one hundred qubits (2013, methodology): “We attribute these to calibration errors of the couplers in the device which vary by about 10% [31].”
Quantum information processing with superconducting circuits: a review (2016, methodology): “As a result, the coherence and entanglement properties have to be investigated by performing various types of experi ments on the machines and their components: Physics experi ments on the hardware [123, 489], and ‘benchmarking’ of the performance by running a range of QA schemes [109, 111, 393, 4”
Quantum Optimization of Fully-Connected Spin Glasses (2014, background): “[22] Richard Harris, MW Johnson, T Lanting, AJ Berkley, J Johansson, P Bunyk, E Tolkacheva, E Ladizinsky, N Ladizinsky, T Oh, et al.”
Entanglement in a Quantum Annealing Processor (2014, background): “The strength and sign of the inductive coupling between pairs of qubits is controlled with magnetic fluxΦco;ij that is provided by an individual on-chip digital-to-analog converter for each coupler [8].”
Natural and artificial atoms for quantum computation (2010, background): “Operation Qubits demonstrated 128 (fabricated) [93], 3 (entangled) Superposition/entangled states Yes/yes One-qubit gates (fidelity) Yes (99%) Two-qubit gates (fidelity) Yes (>90%) [88] Operation temperature mK”