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Scientific Reports

Configuration dependent crosstalk amplification in superconducting quantum processors

Fernando Almaguer Angeles, Pedro R. Dieguez, Akshata Shenoy H., Marcin Pawłowski

Published Oct 21, 2026• 0 citations
Publisher

Abstract

We investigate the behaviour of cross-talk in superconducting quantum processors under repeated and structured gate operations. Using commercially available IBM quantum devices, we observe that sequences of two-qubit gates are associated with a measurable bias in the neighbouring spectator qubits without direct interaction, producing quantifiable changes in neighbouring spectator-qubit measurement outcomes that significantly exceed the corresponding control baselines.

DOI
10.1038/s41598-026-70466-w

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We investigate the behaviour of cross-talk in superconducting quantum processors under repeated and structured gate operations. Using commercially available IBM quantum devices, we observe that sequences of two-qubit gates are associated with a measurable bias in the neighbouring spectator qubits without direct interaction, producing quantifiable changes in neighbouring spectator-qubit measurement outcomes that significantly exceed the corresponding control baselines.
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Quantum devices in the noisy intermediate-scale quantum (NISQ) era are highly susceptible to different types of quantum noise, which directly impact the reliability of experimental results. This work provides a characterization of error behavior arising from quantum noises on IBM's superconducting quantum processor, offering practical insights for algorithm design, benchmarking, and error-mitigation strategies on a real superconducting quantum processor in the NISQ era. The study begins with the measurement of the basis state, without applying any gate, to quantify state-preparation and measurement (SPAM) errors. Additionally, the errors are further quantified due to the application of single-qubit Pauli-X, two-qubit CNOT gate and other multi-qubit Controlled-X gates. Each circuit was executed with 1024 shots, and the percentage error between the expected and observed outputs was computed. The results show that the single-qubit Pauli-X gate exhibits relatively low errors in comparison with the two-qubit CNOT gate, whereas other multi-qubit Controlled-X gates lead to significantly higher deviations. This work also analyzes the noise effect of a fourqubit Controlled-X gate being implemented using a three-qubit Controlled-X gate with an extra auxiliary qubit, and the result shows a significant reduction in the error rate.