Abstract
Abstract
Surface dielectric loss from superconducting transmon qubits is believed to be one of the dominant sources of decoherence. Reducing surface dielectric loss is crucial for achieving a high quality factor and a long relaxation time (T
1), which can be engineered by carefully changing the geometry of a transmon. In this paper, we present a shape-optimization approach to reduce surface dielectric loss in a transmon qubit. The capacitor pads and junction wires of transmons are shaped as spline curves and optimized through the finite-element method and a global optimization algorithm. We find that the participation ratio of capacitor pads and junction wires can be reduced by
15
%
−
18
% and
22
%
−
26
% compared to previous designs, while the overall footprint and anharmonicity are maintained at acceptable values. As a result, the two-level system-limited quality factor and the corresponding T
1 were increased by 21.6%.
Funder
Seoul National University
National Research Foundation of Korea
Subject
Surfaces, Coatings and Films,Acoustics and Ultrasonics,Condensed Matter Physics,Electronic, Optical and Magnetic Materials
Cited by
2 articles.
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