title: Single-quasiparticle trapping in aluminum nanobridge Josephson junctions.
abstract: We present microwave measurements of a high quality factor superconducting resonator incorporating two aluminum nanobridge Josephson junctions in a loop shunted by an on-chip capacitor. Trapped quasiparticles (QPs) shift the resonant frequency, allowing us to probe the trapped QP number and energy distribution and to quantify their lifetimes. We find that the trapped QP population obeys a Gibbs distribution above 75 mK, with non-Poissonian trapping statistics. Our results are in quantitative agreement with the Andreev bound state model of transport, and demonstrate a practical means to quantify on-chip QP populations and validate mitigation strategies in a cryogenic environment.
authors.affiliation: Quantum Nanoelectronics Laboratory, Department of Physics, University of California, Berkeley, California 94720, USA.
authors.forename: E M
authors.initials: EM
authors.lastname: Levenson-Falk
authors.affiliation: Department of Physics, Yale University, New Haven, Connecticut 06520, USA.
authors.forename: F
authors.initials: F
authors.lastname: Kos
authors.affiliation: Quantum Nanoelectronics Laboratory, Department of Physics, University of California, Berkeley, California 94720, USA and Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Mumbai 400005, India.
authors.forename: R
authors.initials: R
authors.lastname: Vijay
authors.affiliation: Department of Physics, Yale University, New Haven, Connecticut 06520, USA.
authors.forename: L
authors.initials: L
authors.lastname: Glazman
authors.affiliation: Quantum Nanoelectronics Laboratory, Department of Physics, University of California, Berkeley, California 94720, USA.
authors.forename: I
authors.initials: I
authors.lastname: Siddiqi