A. Shnirman et al., TUNNELING AND RESONANT-TUNNELING OF FLUXONS IN A LONG JOSEPHSON-JUNCTION, Physical review. B, Condensed matter, 56(22), 1997, pp. 14677-14685
We study fluxon tunneling both across one microshort-type barrier and
resonant tunneling across two barriers. We have derived an effective H
amiltonian (using the inverse scattering transform) to study the effec
t of plasmons on the tunneling. Using a specially derived perturbation
scheme, we found two effects:, (1) Emission of plasmons and, hence, s
uppression of quantum effects. Due to the gap in the plasmon spectrum,
this is an exponentially small effect. (2) Virtual processes involvin
g plasmons' emission and absorption cause an enhancement of the tunnel
ing probability. The magnitude of this enhancement is not exponentiall
y small. We conclude that macroscopic quantum tunneling of fluxons can
be observed. We further predict that fluxons' resonant tunneling acro
ss two barriers can also be observed. This phenomenon provides an idea
l test for the quantum behavior of the fluxons.