SAMOP 2021 – wissenschaftliches Programm
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QI: Fachverband Quanteninformation
QI 10: Certification and Benchmarking of Quantum Systems
QI 10.4: Vortrag
Donnerstag, 23. September 2021, 11:30–11:45, H5
Gate set tomography via Riemannian optimization — •Raphael Brieger1, Martin Kliesch1, and Ingo Roth2 — 1Institute for Theoretical Physics, Heinrich Heine University Düsseldorf, Germany — 2Quantum research centre, Technology Innovation Institute, Abu Dhabi, UAE
Flexible characterization techniques that quantify and identify noise under realistic assumptions are crucial for the development of near term quantum computers. Gate set tomography (GST) has been proposed as a technique that simultaneously extracts tomographic information on an entire set of quantum gates, the state preparation and the measurements under minimal assumptions. We argue that the problem of reconstructing the gate set subject to physicality constraints, such as complete positivity, can naturally be cast as an optimization problem on the complex Stiefel manifold. We develop a second order manifold optimization algorithm that allows us to perform GST accurately from random circuit data. In contrast to traditional approaches our algorithm does not need a structured gate set and an elaborate circuit design to perform GST, while matching the performance of state of the art methods. Furthermore, it can naturally include low-rank constraints on the gate set in order to reduce the scaling problems inherent in quantum process tomography.