[show abstract][hide abstract] ABSTRACT: We study the energy spectrum for an aperiodic Josephson junction ladder, as a
function of frustration. Frustration is brought about by application of a
transverse magnetic field, and aperiodicity is imposed by the arrangement of
plaquettes with two incommensurate areas. We study the effect of the
incommensurate plaquette areas in conjunction with that of the aperiodicity.
The structure of the energy spectrum at deep minima is shown to be described by
a model that treats the plaquettes independently. The energy spectrum is a
quasiperiodic function of frustration; short range correlations in the
arrangement of plaquettes have a small effect on the energy power spectrum.
[show abstract][hide abstract] ABSTRACT: We study an array of inductively coupled Josephson junctions containing a single phase-slip site in the
presence of an alternating current. A phase-slip site with reduced critical current can serve as a permanent
source of solitary pulses which can synchronize the dynamics of an infinitely large array of junctions. We find that for definite values of parameters, increasing the coupling constant may prevent this synchronization in a system with periodic boundary conditions. This dependence on the boundary condition can be used as a coding mechanism and the information can be retrieved elsewhere in the array.
Physical Review B 10/2010; 82 144520:144520. · 3.77 Impact Factor
[show abstract][hide abstract] ABSTRACT: We investigate the origin of fractional Shapiro steps in arrays consisting of a few overdamped Josephson junctions. We show that when the symmetry reduces the equations to that of a single junction equation, only integer steps appear. Otherwise, fractional steps will appear when the evolution equations contain second (or higher) order derivatives or non-sinusoidal terms. We make a point of distinguishing the last two possibilities in the generation of the fractional steps.
Journal of Nonlinear Mathematical Physics Volume Supplement. 01/2008; 15(3):407-416.
[show abstract][hide abstract] ABSTRACT: We study the dynamics of a triangular single-plaquette Josephson-junction array in the development of the
fractional Shapiro steps. We show that synchronization on fractional steps can happen due to an intricate
interplay of the three junctions as the plaquette is made dynamically unsymmetric, either by applying an
external magnetic field or by changing the configuration of external currents. We propose a mechanism for
synchronization when the asymmetry is only due to the frustration induced by the magnetic field.
Physical Review B 12/2007; 76:214511. · 3.77 Impact Factor