Quantum phase slips in a resonant Josephson junction

Physical review. B./Physical review. B, vol. 107

Abstract

We investigate the consequences of resonant tunneling of Cooper pairs on the quantum phase slips occurring in a Josephson junction. The amplitude for quantum tunneling under the Josephson potential barrier is modified by the Landau-Zener amplitude of adiabatic passage through an Andreev level crossing, resulting in the suppression of $2\ensuremath{\pi}$ phase slips. As a consequence, close to resonance, $4\ensuremath{\pi}$ phase slips become the dominant tunneling process. We illustrate this crossover by determining the energy spectrum of a transmon circuit, showing that a residual charge dispersion persists even at perfect transparency.

Authors 2

1. Tereza Vakhtel Aachen Instituut-Lorentz

   Leiden University

   Affiliation as printed

   Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, The Netherlands

2. Bernard van Heck Aachen

   Leiden University · Sapienza University of Rome

   Affiliation as printed

   Dipartimento di Fisica, Universit di Roma La Sapienza, P.le Aldo Moro 5, 00185 Roma, Italy

   Leiden Institute of Physics, Universiteit Leiden, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands