Impact of Absorption due to Zero-Field Splitting on Loss in Dielectrics: A Case Study in Sapphire

Fuente: arXiv
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Main Authors: Turiansky, Mark E., Van de Walle, Chris G.
Format: Preprint
Published: 2025
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author Turiansky, Mark E.
Van de Walle, Chris G.
author_facet Turiansky, Mark E.
Van de Walle, Chris G.
contents The coherence times of superconducting qubits are limited by loss mechanisms, whose microscopic origins have remained elusive. We propose a mechanism caused by transitions between zero-field-split states of paramagnetic impurities or defects. We derive the absorption cross section for a magnetic dipole transition and apply it to calculate the loss tangent. For Cr, Fe, and V impurities in sapphire, we find loss tangents at 4.5 GHz in the range of 10$^{-9}$-10$^{-8}$, comparable to the loss measured in experiments. This value suggests that magnetic loss may be a limiting factor in the coherence times of superconducting qubits.
format Preprint
id arxiv_https___arxiv_org_abs_2504_04610
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Impact of Absorption due to Zero-Field Splitting on Loss in Dielectrics: A Case Study in Sapphire
Turiansky, Mark E.
Van de Walle, Chris G.
Quantum Physics
Materials Science
The coherence times of superconducting qubits are limited by loss mechanisms, whose microscopic origins have remained elusive. We propose a mechanism caused by transitions between zero-field-split states of paramagnetic impurities or defects. We derive the absorption cross section for a magnetic dipole transition and apply it to calculate the loss tangent. For Cr, Fe, and V impurities in sapphire, we find loss tangents at 4.5 GHz in the range of 10$^{-9}$-10$^{-8}$, comparable to the loss measured in experiments. This value suggests that magnetic loss may be a limiting factor in the coherence times of superconducting qubits.
title Impact of Absorption due to Zero-Field Splitting on Loss in Dielectrics: A Case Study in Sapphire
topic Quantum Physics
Materials Science
url https://arxiv.org/abs/2504.04610