Zener enhancement of quantum tunneling in a two-level superconducting circuit.
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.
Ithier
G
G
Quantronics group, Service de Physique de l'Etat Condensé, DSM/DRECAM, CEA Saclay, 91191 Gif-sur-Yvette, France.
Collin
E
E
Joyez
P
P
Vion
D
D
Esteve
D
D
Ankerhold
J
J
Grabert
H
H