Statistics of Strongly Coupled Defects in Superconducting Qubits

Fuente: arXiv
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Autori principali: Weeden, S., Harrison, D. C., Patel, S., Snyder, M., Blackwell, E. J., Spahn, G., Abdullah, S., Takeda, Y., Plourde, B. L. T., Martinis, J. M., McDermott, R.
Natura: Preprint
Pubblicazione: 2025
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author Weeden, S.
Harrison, D. C.
Patel, S.
Snyder, M.
Blackwell, E. J.
Spahn, G.
Abdullah, S.
Takeda, Y.
Plourde, B. L. T.
Martinis, J. M.
McDermott, R.
author_facet Weeden, S.
Harrison, D. C.
Patel, S.
Snyder, M.
Blackwell, E. J.
Spahn, G.
Abdullah, S.
Takeda, Y.
Plourde, B. L. T.
Martinis, J. M.
McDermott, R.
contents Decoherence in superconducting qubits is dominated by defects that reside at amorphous interfaces. Interaction with discrete defects results in dropouts that complicate qubit operation and lead to nongaussian tails in the distribution of qubit energy relaxation time $T_1$ that degrade system performance. Spectral diffusion of defects over time leads to fluctuations in $T_1$, posing a challenge for calibration. In this work, we measure the energy relaxation of flux-tunable transmons over a range of operating frequencies. We vary qubit geometry to change the interface participation ratio by more than an order of magnitude. Our results are consistent with loss dominated by discrete interfacial defects. Moreover, we are able to localize the dominant defects to within 500 nm of the qubit junctions, where residues from liftoff are present. These results motivate new approaches to qubit junction fabrication that avoid the residues intrinsic to the liftoff process.
format Preprint
id arxiv_https___arxiv_org_abs_2506_00193
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Statistics of Strongly Coupled Defects in Superconducting Qubits
Weeden, S.
Harrison, D. C.
Patel, S.
Snyder, M.
Blackwell, E. J.
Spahn, G.
Abdullah, S.
Takeda, Y.
Plourde, B. L. T.
Martinis, J. M.
McDermott, R.
Quantum Physics
Mesoscale and Nanoscale Physics
Decoherence in superconducting qubits is dominated by defects that reside at amorphous interfaces. Interaction with discrete defects results in dropouts that complicate qubit operation and lead to nongaussian tails in the distribution of qubit energy relaxation time $T_1$ that degrade system performance. Spectral diffusion of defects over time leads to fluctuations in $T_1$, posing a challenge for calibration. In this work, we measure the energy relaxation of flux-tunable transmons over a range of operating frequencies. We vary qubit geometry to change the interface participation ratio by more than an order of magnitude. Our results are consistent with loss dominated by discrete interfacial defects. Moreover, we are able to localize the dominant defects to within 500 nm of the qubit junctions, where residues from liftoff are present. These results motivate new approaches to qubit junction fabrication that avoid the residues intrinsic to the liftoff process.
title Statistics of Strongly Coupled Defects in Superconducting Qubits
topic Quantum Physics
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2506.00193