  Single-file transport in pore-like structures constitute an important topic
for both theory and experiment. For hardcore interacting particles, a good
understanding of the collective dynamics has been achieved recently. Here we
study how softness in the particle interaction affects the emergent transport
behavior. To this end, we investigate the driven Brownian motion of particles
in a periodic potential. The particles interact via a repulsive softcore
potential with a shape corresponding to a smoothed rectangular barrier. This
shape allows us to elucidate effects of mutual particle penetration and
particle crossing in a controlled manner. We find that even weak deviations
from the hardcore case can have a strong impact on the particle current.
Despite this fact, the knowledge about the transport in a corresponding
hardcore system is shown to be useful to describe and interpret our findings
for the softcore case. This is achieved by assigning a thermodynamic effective
size to the particles based on the equilibrium density functional of hard
spheres.

Statistical Mechanics;Soft Condensed Matter