Effect of magnetic field on macroscopic quantum tunneling escape time in small Josephson junctions
Abstract
We study the phenomenon of macroscopic quantum tunneling (MQT) in a finitesize Josephson junction (JJ) with an externally applied magnetic field. As is well known, the problem of MQT in a pointlike JJ is reduced to the study of the underbarrier motion of a quantum particle in the washboard potential. In the case of a finitesize JJ placed in magnetic field, this problem is considerably more complex since, besides the phase, the potential itself depends on space variables. We find the general expressions both for the crossover temperature T_{0} between thermally activated and MQT regimes and the escape time τ_{esc} . It turns out that in the proximity of particular values of magnetic field, the crossover temperature can vary nonmonotonically.
 Publication:

Physical Review B
 Pub Date:
 August 2008
 DOI:
 10.1103/PhysRevB.78.054521
 Bibcode:
 2008PhRvB..78e4521O
 Keywords:

 74.50.+r;
 Tunneling phenomena;
 point contacts weak links Josephson effects