title: Zener enhancement of quantum tunneling in a two-level superconducting circuit.
abstract: We have investigated the macroscopic quantum tunneling (MQT) of the phase across a Josephson junction embedded in a superconducting circuit. This system is equivalent to a spin 1/2 particle in a potential energy well. The MQT escape rate of such a particle was recently predicted to be strongly modified when a crossing of its inner Zeeman levels occurs while tunneling. In this regime, we observe a significant enhancement of the MQT rate and compare it to theory.
authors.affiliation: Quantronics group, Service de Physique de l'Etat Condensé, DSM/DRECAM, CEA Saclay, 91191 Gif-sur-Yvette, France.
authors.forename: G
authors.initials: G
authors.lastname: Ithier
authors.forename: E
authors.initials: E
authors.lastname: Collin
authors.forename: P
authors.initials: P
authors.lastname: Joyez
authors.forename: D
authors.initials: D
authors.lastname: Vion
authors.forename: D
authors.initials: D
authors.lastname: Esteve
authors.forename: J
authors.initials: J
authors.lastname: Ankerhold
authors.forename: H
authors.initials: H
authors.lastname: Grabert