Recovering Quantum Gates from Few Average Gate Fidelities

Roth , Kueng R, Kimmel S, Liu YK, Gross D, Eisert J, Kliesch M (2018)

Publication Type: Journal article

Publication year: 2018

Journal

Physical Review Letters American Physical Society

Book Volume: 121

Article Number: 170502

Journal Issue: 17

DOI: 10.1103/PhysRevLett.121.170502

Abstract

Characterizing quantum processes is a key task in the development of quantum technologies, especially at the noisy intermediate scale of today's devices. One method for characterizing processes is randomized benchmarking, which is robust against state preparation and measurement errors and can be used to benchmark Clifford gates. Compressed sensing techniques achieve full tomography of quantum channels essentially at optimal resource efficiency. In this Letter, we show that the favorable features of both approaches can be combined. For characterizing multiqubit unitary gates, we provide a rigorously guaranteed and practical reconstruction method that works with an essentially optimal number of average gate fidelities measured with respect to random Clifford unitaries. Moreover, for general unital quantum channels, we provide an explicit expansion into a unitary 2-design, allowing for a practical and guaranteed reconstruction also in that case. As a side result, we obtain a new statistical interpretation of the unitarity - a figure of merit characterizing the coherence of a process.

Involved external institutions

Freie Universität Berlin DE Germany (DE) California Institute of Technology (Caltech) US United States (USA) (US) Middlebury College US United States (USA) (US) National Institute of Standards and Technology (NIST) US United States (USA) (US) Universität zu Köln DE Germany (DE) University of Gdańsk / Uniwersytet Gdański PL Poland (PL)

How to cite

APA:

Roth, ., Kueng, R., Kimmel, S., Liu, Y.-K., Gross, D., Eisert, J., & Kliesch, M. (2018). Recovering Quantum Gates from Few Average Gate Fidelities. Physical Review Letters, 121(17). https://dx.doi.org/10.1103/PhysRevLett.121.170502

MLA:

Roth, , et al. "Recovering Quantum Gates from Few Average Gate Fidelities." Physical Review Letters 121.17 (2018).

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