title: Measurement and control of quasiparticle dynamics in a superconducting qubit.
abstract: Superconducting circuits have attracted growing interest in recent years as a promising candidate for fault-tolerant quantum information processing. Extensive efforts have always been taken to completely shield these circuits from external magnetic fields to protect the integrity of the superconductivity. Here we show vortices can improve the performance of superconducting qubits by reducing the lifetimes of detrimental single-electron-like excitations known as quasiparticles. Using a contactless injection technique with unprecedented dynamic range, we quantitatively distinguish between recombination and trapping mechanisms in controlling the dynamics of residual quasiparticle, and show quantized changes in quasiparticle trapping rate because of individual vortices. These results highlight the prominent role of quasiparticle trapping in future development of superconducting qubits, and provide a powerful characterization tool along the way.
authors.affiliation: Department of Applied Physics and Physics, Yale University, 401 Becton Center, 15 Prospect Street, New Haven, Connecticut 06520, USA.
authors.forename: C
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Applied Physics and Physics, Yale University, 401 Becton Center, 15 Prospect Street, New Haven, Connecticut 06520, USA.
authors.forename: Y Y
authors.initials: YY
authors.lastname: Gao
authors.affiliation: Department of Applied Physics and Physics, Yale University, 401 Becton Center, 15 Prospect Street, New Haven, Connecticut 06520, USA.
authors.forename: I M
authors.initials: IM
authors.lastname: Pop
authors.affiliation: Department of Applied Physics and Physics, Yale University, 401 Becton Center, 15 Prospect Street, New Haven, Connecticut 06520, USA.
authors.forename: U
authors.initials: U
authors.lastname: Vool
authors.affiliation: Department of Applied Physics and Physics, Yale University, 401 Becton Center, 15 Prospect Street, New Haven, Connecticut 06520, USA.
authors.forename: C
authors.initials: C
authors.lastname: Axline
authors.affiliation: Department of Applied Physics and Physics, Yale University, 401 Becton Center, 15 Prospect Street, New Haven, Connecticut 06520, USA.
authors.forename: T
authors.initials: T
authors.lastname: Brecht
authors.affiliation: Department of Applied Physics and Physics, Yale University, 401 Becton Center, 15 Prospect Street, New Haven, Connecticut 06520, USA.
authors.forename: R W
authors.initials: RW
authors.lastname: Heeres
authors.affiliation: Department of Applied Physics and Physics, Yale University, 401 Becton Center, 15 Prospect Street, New Haven, Connecticut 06520, USA.
authors.forename: L
authors.initials: L
authors.lastname: Frunzio
authors.affiliation: Department of Applied Physics and Physics, Yale University, 401 Becton Center, 15 Prospect Street, New Haven, Connecticut 06520, USA.
authors.forename: M H
authors.initials: MH
authors.lastname: Devoret
authors.affiliation: Peter Grünberg Institut (PGI-2), Forschungszentrum Jülich, 52425 Jülich, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Catelani
authors.affiliation: Department of Applied Physics and Physics, Yale University, 401 Becton Center, 15 Prospect Street, New Haven, Connecticut 06520, USA.
authors.forename: L I
authors.initials: LI
authors.lastname: Glazman
authors.affiliation: Department of Applied Physics and Physics, Yale University, 401 Becton Center, 15 Prospect Street, New Haven, Connecticut 06520, USA.
authors.forename: R J
authors.initials: RJ
authors.lastname: Schoelkopf