Passage Times for Polymer Translocation Pulled through a Narrow Pore

TL;DR

This paper investigates how the passage time of a polymer through a narrow pore depends on polymer length and pulling force, revealing different scaling regimes and the role of chain tension dynamics near the pore.

Contribution

It introduces a detailed analysis of passage time scaling laws for polymer translocation under varying forces, emphasizing the impact of chain tension memory effects.

Findings

At small to moderate forces, passage time scales as N^{2+ν}

At strong forces, passage time scales as N^2/F

Memory effects in chain tension influence translocation dynamics

Abstract

We study the passage times of a translocating polymer of length $N$ in three dimensions, while it is pulled through a narrow pore with a constant force $F$ applied to one end of the polymer. At small to moderate forces, satisfying the condition $FN^{\nu}/k_BT\lesssim1$, where $\nu\approx0.588$ is the Flory exponent for the polymer, we find that $\tau_N$, the mean time the polymer takes to leave the pore, scales as $N^{2+\nu}$ independent of $F$, in agreement with our earlier result for F=0. At strong forces, i.e., for $FN^{\nu}/k_BT\gg1$, the behaviour of the passage time crosses over to $\tau_N\sim N^2/F$. We show here that these behaviours stem from the polymer dynamics at the immediate vicinity of the pore -- in particular, the memory effects in the polymer chain tension imbalance across the pore.