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Main Authors: Wolff, Oliver F., Mantry, Harshvardhan, Raja, Rahim, Peng, Wei-Hsiang, Singirikonda, Kaushik, Lee, Seungkyun, Sudhaman, Shishir, Goncalves, Rafael, Huang, Pinshane Y., Kou, Angela, Pfaff, Wolfgang
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2602.11469
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author Wolff, Oliver F.
Mantry, Harshvardhan
Raja, Rahim
Peng, Wei-Hsiang
Singirikonda, Kaushik
Lee, Seungkyun
Sudhaman, Shishir
Goncalves, Rafael
Huang, Pinshane Y.
Kou, Angela
Pfaff, Wolfgang
author_facet Wolff, Oliver F.
Mantry, Harshvardhan
Raja, Rahim
Peng, Wei-Hsiang
Singirikonda, Kaushik
Lee, Seungkyun
Sudhaman, Shishir
Goncalves, Rafael
Huang, Pinshane Y.
Kou, Angela
Pfaff, Wolfgang
contents Materials defects in Josephson junctions (JJs), often referred to as two-level systems (TLS), couple to superconducting qubits and are a critical bottleneck for scalable quantum processors. Despite their importance, understanding the microscopic sources of TLS and how to mitigate them has remained a major challenge. Here, we demonstrate a high-throughput, correlated approach to trace the microstructural origins of strongly-coupled TLS in Josephson circuits. We assembled a massive dataset of TLS across 6,000 Al/AlOx/Al JJs and more than 600 atomic resolution transmission electron microscopy images. We statistically link fabrication, microstructure, and TLS occurrence, revealing a strong correlation between Al electrode thickness, Al grain size, and TLS density. Correspondingly, we find a two-thirds reduction in TLS prompted by a change in electrode fabrication parameters. These results demonstrate a robust, data-driven methodology to understand and control defects in quantum circuits and pave the way for significantly reducing TLS density.
format Preprint
id arxiv_https___arxiv_org_abs_2602_11469
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Structural control of two-level defect density revealed by high-throughput correlative measurements of Josephson junctions
Wolff, Oliver F.
Mantry, Harshvardhan
Raja, Rahim
Peng, Wei-Hsiang
Singirikonda, Kaushik
Lee, Seungkyun
Sudhaman, Shishir
Goncalves, Rafael
Huang, Pinshane Y.
Kou, Angela
Pfaff, Wolfgang
Quantum Physics
Mesoscale and Nanoscale Physics
Materials Science
Materials defects in Josephson junctions (JJs), often referred to as two-level systems (TLS), couple to superconducting qubits and are a critical bottleneck for scalable quantum processors. Despite their importance, understanding the microscopic sources of TLS and how to mitigate them has remained a major challenge. Here, we demonstrate a high-throughput, correlated approach to trace the microstructural origins of strongly-coupled TLS in Josephson circuits. We assembled a massive dataset of TLS across 6,000 Al/AlOx/Al JJs and more than 600 atomic resolution transmission electron microscopy images. We statistically link fabrication, microstructure, and TLS occurrence, revealing a strong correlation between Al electrode thickness, Al grain size, and TLS density. Correspondingly, we find a two-thirds reduction in TLS prompted by a change in electrode fabrication parameters. These results demonstrate a robust, data-driven methodology to understand and control defects in quantum circuits and pave the way for significantly reducing TLS density.
title Structural control of two-level defect density revealed by high-throughput correlative measurements of Josephson junctions
topic Quantum Physics
Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2602.11469