aiqbench analysis
This paper introduces a method for characterizing noise in error-corrected logical qubits, applied to a single-qubit gate set in the Steane code on a Quantinuum trapped-ion processor. Its most useful result for readers is methodological: the emulator and hardware data disagree on whether logical non-Markovian and coherent errors appear, so predicting real-world logical performance depends on how well the emulator models the physical error sources. The work is a concrete step toward judging whether logical operations are reliable enough for deeper circuits, not a demonstration of a usable quantum advantage.
Logical gate set tomography
arXiv:2610.19034v1 Announce Type: new Abstract: Quantum error correction (QEC) can strongly suppress noise, but predicting whether a computation succeeds requires understanding not only how much effective noise persists after QEC, but what form that noise takes. To thoroughly characterize this noise, we introduce logical gate set tomography (``logical GST''). Logical GST produces detailed representations of noisy logical operations that can be used to derive higher-level metrics, such as gate fidelity and diamond distance, and to test for non-Markovian and coherent logical errors. We use logical GST to obtain the first full, self-consistent characterization of a universal single-qubit logical gate set, implemented in the seven-qubit Steane code using Quantinuum System Model H1, a 20-qubit trapped-ion quantum processor. In the experimental data from H1, logical GST identified predominantly logical Pauli-stochastic errors, found no evidence of logical non-Markovianity, and detected weak potential signatures of coherent logical error. By contrast, higher-shot datasets generated with Quantinuum's detailed system emulator, identify mechanisms for weak but statistically significant logical non-Markovianity and strong evidence of coherent logical error. Finally, we use logical GST to perform error attribution with the system emulator, revealing how specific physical error sources shape logical error mechanisms.
Authors:Piper C. Wysocki, Juan Gonzalez De Mendoza, Karl Mayer, Natalie C. Brown, Ciaran Ryan-Anderson, Jalan A. Ziyad, Jordan H. Hines, Daniel G. Hothem, Corey I. Ostrove, Timothy J. Proctor, Kevin C. Young, Robin J. Blume-Kohout, Charles H. Baldwin, Kenneth M. Rudinger
Abstract:Quantum error correction (QEC) can strongly suppress noise, but predicting whether a computation succeeds requires understanding not only how much effective noise persists after QEC, but what form that noise takes. To thoroughly characterize this noise, we introduce logical gate set tomography (``logical GST''). Logical GST produces detailed representations of noisy logical operations that can be used to derive higher-level metrics, such as gate fidelity and diamond distance, and to test for non-Markovian and coherent logical errors. We use logical GST to obtain the first full, self-consistent characterization of a universal single-qubit logical gate set, implemented in the seven-qubit Steane code using Quantinuum System Model H1, a 20-qubit trapped-ion quantum processor. In the experimental data from H1, logical GST identified predominantly logical Pauli-stochastic errors, found no evidence of logical non-Markovianity, and detected weak potential signatures of coherent logical error. By contrast, higher-shot datasets generated with Quantinuum's detailed system emulator, identify mechanisms for weak but statistically significant logical non-Markovianity and strong evidence of coherent logical error. Finally, we use logical GST to perform error attribution with the system emulator, revealing how specific physical error sources shape logical error mechanisms.
arXiv:2610.19034 [quant-ph]
(or arXiv:2610.19034v1 [quant-ph] for this version)
https://doi.org/10.48550/arXiv.2610.19034 arXiv-issued DOI via DataCite (pending registration)
Full text under the publisher's open licence · 244 words
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