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Robustness of superconducting quantum modes against direct quasiparticle injection

U. Patel, Ibrahim Nsanzineza, Maxim Vavilov +2 more

Bulletin of the American Physical SocietyMar 17, 20160 citations

Superconducting resonators with trapped vortices under direct injection of quasiparticles

Ibrahim Nsanzineza, Umesh Patel, Kenneth Dodge +2 more

Bulletin of the American Physical SocietyMar 17, 20160 citations

Quasiparticle Lifetime and Noise in Tantalum High Q Superconducting Resonators

R. Barends, J. J. A. Baselmans, S. J. C. Yates +3 more

Journal of Low Temperature PhysicsJan 9, 20083 citations

High-energy quasiparticle injection into mesoscopic superconductors

Loren D. Alegria, Charlotte G. L. Bøttcher, Andrew K. Saydjari +5 more

arXiv:2005.00584Nature NanotechnologyJan 18, 202161 citations

Vortices and Quasiparticles in Superconducting Microwave Resonators

Ibrahim Nsanzineza

Superconducting resonators with high quality factors are of great interest in many areas. However, the quality factor of the resonator can be weakened by many dissipation channels including trapped magnetic flux vortices and nonequilibrium quasiparticles which can significantly impact the performance of superconducting microwave resonant circuits and qubits at millikelvin temperatures. Quasiparticles result in excess loss, reducing resonator quality factors and qubit lifetimes. Vortices trapped near regions of large microwave currents also contribute excess loss. However, vortices located in current-free areas in the resonator or in the ground plane of a device can actually trap quasiparticles and lead to a reduction in the quasiparticle loss. In this thesis, we will describe experiments involving the controlled trapping of vortices for reducing quasiparticle density in the superconducting resonators. We provide a model for the simulation of reduction of nonequilibrium quasiparticles by vortices. In our experiments, quasiparticles are generated either by stray pair-breaking radiation or by direct injection using normal-insulator-superconductor (NIS)-tunnel junctions.Superconducting resonators with high quality factors are of great interest in many areas. However, the quality factor of the resonator can be weakened by many dissipation channels including trapped magnetic flux vortices and nonequilibrium quasiparticles which can significantly impact the performance of superconducting microwave resonant circuits and qubits at millikelvin temperatures. Quasiparticles result in excess loss, reducing resonator quality factors and qubit lifetimes. Vortices trapped near regions of large microwave currents also contribute excess loss. However, vortices located in current-free areas in the resonator or in the ground plane of a device can actually trap quasiparticles and lead to a reduction in the quasiparticle loss. In this thesis, we will describe experiments involving the controlled trapping of vortices for reducing quasiparticle density in the superconducting resonators. We provide a model for the simulation of reduction of nonequilibrium quasiparticles by vortices. In our experiments, quasiparticles are generated either by stray pair-breaking radiation or by direct injection using normal-insulator-superconductor (NIS)-tunnel junctions.

Jan 1, 20163 citations

Power and temperature dependence of High Q superconducting resonators

Ashish Alexander, Christopher Weddle, Christopher J. K. Richardson

Bulletin of the American Physical SocietyMar 3, 20200 citations

Robustness of superconducting high-Q resonators against direct quasiparticle injection

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