The dynamically asymmetric SQUID: Münchhausen effect
Abstract
We report on a complex zero temperature decay channel of a classical object in a metastable state coupled to a quantum degree of freedom. This setting can be realized in a dcSQUID where both Josephson junctions have identical critical currents I_{c} but feature strongly asymmetric dynamical parameters; more precisely, selecting both parameters C and 1 / R adequately large for one and small for the other junction makes the first junction behave essentially classically but lets quantum effects be present for the second one. The decay process is initiated by the tunneling of the quantum junction, which distorts the trapping potential of the classical junction; the metastable state of the latter then becomes unstable if the distortion is large enough. We present the dynamical phase diagram of this system providing the dependence of this decay channel on the external bias current I and on the coupling strength between the two junctions, determined by the loop inductance L.
 Publication:

Physica C Superconductivity
 Pub Date:
 April 2008
 DOI:
 10.1016/j.physc.2007.11.034
 arXiv:
 arXiv:0801.4886
 Bibcode:
 2008PhyC..468..705T
 Keywords:

 SQUID;
 Macroscopic quantum tunneling;
 85.25.Dq;
 74.50.+r;
 Superconducting quantum interference devices;
 Tunneling phenomena;
 point contacts weak links Josephson effects;
 Condensed Matter  Superconductivity
 EPrint:
 4 pages, 3 figures, to appear in the VORTEX V proceedings in Physica C