title: Flux noise probed with real time qubit tomography in a Josephson phase qubit.
abstract: We measure the dependence of qubit phase coherence and flux noise on inductor loop geometry. While wider inductor traces change neither the flux noise power spectrum nor the qubit dephasing time, increased inductance leads to a simultaneous increase in both. Using our new tomographic protocol for measuring low frequency flux noise, we make a direct comparison between the flux noise spectrum and qubit phase decay, finding agreement within 10% of theory.
authors.affiliation: Department of Physics, University of California, Santa Barbara, California 93106-9530, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Sank
authors.forename: R
authors.initials: R
authors.lastname: Barends
authors.forename: Radoslaw C
authors.initials: RC
authors.lastname: Bialczak
authors.forename: Yu
authors.initials: Y
authors.lastname: Chen
authors.forename: J
authors.initials: J
authors.lastname: Kelly
authors.forename: M
authors.initials: M
authors.lastname: Lenander
authors.forename: E
authors.initials: E
authors.lastname: Lucero
authors.forename: Matteo
authors.initials: M
authors.lastname: Mariantoni
authors.forename: A
authors.initials: A
authors.lastname: Megrant
authors.forename: M
authors.initials: M
authors.lastname: Neeley
authors.forename: P J J
authors.initials: PJ
authors.lastname: O'Malley
authors.forename: A
authors.initials: A
authors.lastname: Vainsencher
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.forename: J
authors.initials: J
authors.lastname: Wenner
authors.forename: T C
authors.initials: TC
authors.lastname: White
authors.forename: T
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Yi
authors.initials: Y
authors.lastname: Yin
authors.forename: A N
authors.initials: AN
authors.lastname: Cleland
authors.forename: John M
authors.initials: JM
authors.lastname: Martinis