  Iso-flux tension propagation (IFTP) theory and Langevin dynamics (LD)
simulations are employed to study the dynamics of channel-driven polymer
translocation in which a polymer translocates into a narrow channel and the
monomers in the channel experience a driving force $f_{\rm c}$. In the high
driving force limit, regardless of the channel width, IFTP theory predicts
$\tau\propto f_{\textrm{c}}^{\beta}$ for the translocation time, where
$\beta=-1$ is the force scaling exponent. Moreover, LD data show that for a
very narrow channel fitting only a single file of monomers, the entropic force
due to the subchain inside the channel does not play a significant role in the
translocation dynamics, and the force exponent $\beta= -1$ regardless of the
force magnitude. As the channel width increases the number of possible spatial
configurations of the subchain inside the channel becomes significant, and the
resulting entropic force causes the force exponent to drop below unity.
