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.
Versions
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BibTeX
@misc{lisenfeld2026readout,
title = {{Readout failures in superconducting qubits due to TLS-defects in tunnel junctions}},
author = {J. Lisenfeld and A. K. Händel and A. Bilmes and A. V. Ustinov},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2605.02755},
eprint = {2605.02755},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2605.02755},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Readout failures in superconducting qubits due to TLS-defects in tunnel junctions
AU - J. Lisenfeld
AU - A. K. Händel
AU - A. Bilmes
AU - A. V. Ustinov
PY - 2026
DA - 2026/09/03
PB - arXiv
DO - 10.48550/arxiv.2605.02755
UR - https://arxiv.org/abs/2605.02755
AB - 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.
ER -