Readout failures in superconducting qubits due to TLS-defects in tunnel junctions

Abstract:Material defects give rise to parasitic two-level systems (TLS) which present a major source of decoherence in superconducting qubits. Here, we study a strongly coupled TLS that resides in the tunnel barrier of transmon qubit. We use multi-photon spectroscopy and TLS strain tuning to explore the rich spectrum of the interacting three-partite system consisting of TLS, qubit, and its readout resonator. This reveals a strong effective resonant coupling between the TLS and the qubit's readout resonator which dresses the resonator states and results in a resonance frequency shift that spoils the readout signal. Our finding presents yet another way how material defects can interfere with qubit operation and hinder the realization of solid-state quantum processors.

Quantum Physics (quant-ph); Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Superconductivity (cond-mat.supr-con)

arXiv:2605.02755 [quant-ph]

(or arXiv:2605.02755v2 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2605.02755 Focus to learn more arXiv-issued DOI via DataCite

https://doi.org/10.1103/ypm5-lh8d Focus to learn more DOI(s) linking to related resources

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