Dielectric loss from defects and impurities
ORAL
Abstract
Identifying the microscopic mechanisms that lead to dielectric loss in superconducting qubits is essential to improve their coherence times. The presence of defects and impurities is inextricably linked to loss, yet the exact loss mechanism is unclear. Defects and impurities in insulating material can be charged: we propose a mechanism by which charged centers can couple to the microwave fields in the qubit via the release of acoustic phonons. The estimated loss tangent for this process is in good agreement with high-precision measurements of bulk loss in sapphire. We implement a search for alternative materials with lower loss and find that diamond, cubic BN, AlN, and SiC are potentially promising.
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Publication: M. E. Turiansky and C. G. Van de Walle, APL Quantum 1, 026114 (2024).
Presenters
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Mark E Turiansky
University of California, Santa Barbara, Materials Department, University of California, Santa Barbara, CA 93106-5050, U.S.A.
Authors
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Mark E Turiansky
University of California, Santa Barbara, Materials Department, University of California, Santa Barbara, CA 93106-5050, U.S.A.
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Chris G Van de Walle
University of California, Santa Barbara, Materials Department, University of California, Santa Barbara, CA 93106-5050, U.S.A.