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Main Authors: Devra, Amit, Van Damme, Léo, Ende, Frederik vom, Malvetti, Emanuel, Glaser, Steffen J.
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2411.05404
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author Devra, Amit
Van Damme, Léo
Ende, Frederik vom
Malvetti, Emanuel
Glaser, Steffen J.
author_facet Devra, Amit
Van Damme, Léo
Ende, Frederik vom
Malvetti, Emanuel
Glaser, Steffen J.
contents We investigate the tomography of unknown unitary quantum processes within the framework of a finite-dimensional Wigner-type representation. This representation provides a rich visualization of quantum operators by depicting them as shapes assembled as a linear combination of spherical harmonics. These shapes can be experimentally tomographed using a scanning-based phase-space tomography approach. However, so far, this approach was limited to $\textit{known}$ target processes and only provided information about the controlled version of the process rather than the process itself. To overcome this limitation, we introduce a general protocol to extend Wigner tomography to $\textit{unknown}$ unitary processes. This new method enables experimental tomography by combining a set of experiments with classical post-processing algorithms introduced herein to reconstruct the unknown process. We also demonstrate the tomography approach experimentally on IBM quantum devices and present the specific calibration circuits required for quantifying undesired errors in the measurement outcomes of these demonstrations.
format Preprint
id arxiv_https___arxiv_org_abs_2411_05404
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Theory and Experimental Demonstration of Wigner Tomography of Unknown Unitary Quantum Gates
Devra, Amit
Van Damme, Léo
Ende, Frederik vom
Malvetti, Emanuel
Glaser, Steffen J.
Quantum Physics
We investigate the tomography of unknown unitary quantum processes within the framework of a finite-dimensional Wigner-type representation. This representation provides a rich visualization of quantum operators by depicting them as shapes assembled as a linear combination of spherical harmonics. These shapes can be experimentally tomographed using a scanning-based phase-space tomography approach. However, so far, this approach was limited to $\textit{known}$ target processes and only provided information about the controlled version of the process rather than the process itself. To overcome this limitation, we introduce a general protocol to extend Wigner tomography to $\textit{unknown}$ unitary processes. This new method enables experimental tomography by combining a set of experiments with classical post-processing algorithms introduced herein to reconstruct the unknown process. We also demonstrate the tomography approach experimentally on IBM quantum devices and present the specific calibration circuits required for quantifying undesired errors in the measurement outcomes of these demonstrations.
title Theory and Experimental Demonstration of Wigner Tomography of Unknown Unitary Quantum Gates
topic Quantum Physics
url https://arxiv.org/abs/2411.05404