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arXiv · 1405.0256

Trapping a single vortex and reducing quasiparticles in a superconducting resonator

I. Nsanzineza·B. L. T. Plourde
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Abstract

Vortices trapped in thin-film superconducting microwave resonators can have a significant influence on the resonator performance. Using a variable-linewidth geometry for a weakly coupled resonator we are able to observe the effects of a single vortex trapped in the resonator through field cooling. For resonant modes where the vortex is near a current antinode, the presence of even a single vortex leads to a measurable decrease in the quality factor and a dispersive shift of the resonant frequency. For modes with the vortex located at a current node, the presence of the vortex results in no detectable excess loss and, in fact, produces an increase in the quality factor. We attribute this enhancement to a reduction in the density of nonequilibrium quasiparticles in the resonator due to the suppressed gap from the vortex.

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I. Nsanzineza, B. L. T. Plourde. 2014-11-04. Trapping a single vortex and reducing quasiparticles in a superconducting resonator. https://doi.org/10.1103/physrevlett.113.117002

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