2007/02/28 by Roger H. Koch, David P. DiVincenzo, John Clarke · 2 citations
Physics and Astronomy · #cond-mat.supr-con #quant-ph
paper · pdf · doi:10.1103/physrevlett.98.267003
16 pages, 4 figures; v2: Various minor changes. Physical Review Letters, in press
arxiv created 2007/05/15 · arxiv updated 2009/12/01
We propose a model for 1/f flux noise in superconducting devices (f is frequency). The noise is generated by the magnetic moments of electrons in defect states which they occupy for a wide distribution of times before escaping. A trapped electron occupies one of the two Kramers-degenerate ground states, between which the transition rate is negligible at low temperature. As a result, the magnetic moment orientation is locked. Simulations of the noise produced by randomly oriented defects with a density of 5*1017 m-2 yield 1/f noise magnitudes in good agreement with experiments.