  Previous work shows that a net directed motion arises from a system of
individual particles undergoing run-and-tumble dynamics in the presence of an
array of asymmetric barriers. Here, we show that when the individual particle
is replaced by a chain of particles linked to each other by spring forces
(polymer), the rectification is enhanced. It is found that the rectification
increases when the number of particles in each polymer, as well as its length,
increases. In addition, the rectification increases when the size of the
opening between neighboring funnel tips, lo, decreases. Interestingly, if the
conformal entropic difference exceeds the thermal diffusion, net directed
motion is observed even when the run-and-tumble dynamics approaches Brownian
motion. Also, when the inelastic collisions between the particles and the
barriers are replaced by elastic collisions, a reversed rectification is
observed.
