Witnessing and quantifying stellar rank with the Wigner function
Abstract
Quantifying non-Gaussianity is essential for assessing the computational power of bosonic quantum systems. We introduce a framework to witness and quantify non-Gaussianity from displaced parity measurements, and we directly apply it to experimental data obtained with superconducting cavities. Our method estimates fidelities with target pure states from the displaced parity measurements, enabling certification of non-Gaussianity via the stellar rank. We further introduce refined witnesses computed by measuring the value of the Wigner function at a few points, providing efficient certification tools outperforming existing ones. Applying these techniques to Fock, binomial, cat, and GKP experimental data, we rigorously certify non-Gaussian resources and establish a stellar rank of $8$ for a GKP state, setting a new benchmark across all quantum platforms. Our methods enable a rigorous quantification of non-Gaussian quantum resources directly applicable to superconducting devices.
Related
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BibTeX
@misc{hahn2026witnessing,
title = {{Witnessing and quantifying stellar rank with the Wigner function}},
author = {Oliver Hahn and Alex Maltesson and Varun Upreti and Marike Ellerbroek and Alessandro Ferraro and Saleh Rahimi-Keshari and Ulysse Chabaud and Giulia Ferrini},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.40827},
eprint = {2610.40827},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.40827},
}
RIS
TY - UNPB
TI - Witnessing and quantifying stellar rank with the Wigner function
AU - Oliver Hahn
AU - Alex Maltesson
AU - Varun Upreti
AU - Marike Ellerbroek
AU - Alessandro Ferraro
AU - Saleh Rahimi-Keshari
AU - Ulysse Chabaud
AU - Giulia Ferrini
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2610.40827
UR - https://arxiv.org/abs/2610.40827
AB - Quantifying non-Gaussianity is essential for assessing the computational power of bosonic quantum systems. We introduce a framework to witness and quantify non-Gaussianity from displaced parity measurements, and we directly apply it to experimental data obtained with superconducting cavities. Our method estimates fidelities with target pure states from the displaced parity measurements, enabling certification of non-Gaussianity via the stellar rank. We further introduce refined witnesses computed by measuring the value of the Wigner function at a few points, providing efficient certification tools outperforming existing ones. Applying these techniques to Fock, binomial, cat, and GKP experimental data, we rigorously certify non-Gaussian resources and establish a stellar rank of $8$ for a GKP state, setting a new benchmark across all quantum platforms. Our methods enable a rigorous quantification of non-Gaussian quantum resources directly applicable to superconducting devices.
ER -