  We consider a simple model for examining the effects of quenched disorder on
drag consisting of particles interacting via a Yukawa potential that are placed
in two coupled one-dimensional channels. The particles in one channel are
driven and experience a drag from the undriven particles in the second channel.
In the absence of pinning, for a finite driving force there is no pinned phase;
instead, there are two dynamical regimes of completely coupled or locked flow
and partially coupled flow. When pinning is added to one or both channels, we
find that a remarkably rich variety of dynamical phases and drag effects arise
that can be clearly identified by features in the velocity force curves. The
presence of quenched disorder in only the undriven channel can induce a pinned
phase in both channels. Above the depinning transition, the drag on the driven
particles decreases with increasing pinning strength, and for high enough
pinning strength, the particles in the undriven channel reach a reentrant
pinned phase which produces a complete decoupling of the channels. We map out
the dynamic phase diagrams as a function of pinning strength and the density of
pinning in each channel. Our results may be relevant for understanding drag
coupling in 1D Wigner crystal phases, and the effects we observe could also be
explored using colloids in coupled channels produced with optical arrays,
vortices in nanostructured superconductors, or other layered systems where drag
effects arise.

Soft Condensed Matter;Mesoscale and Nanoscale Physics