Theory of polymer translocation through a flickering nanopore under an alternating driving force

TL;DR

This paper develops a theoretical model for polymer translocation through a flickering nanopore under an oscillating driving force, revealing how oscillation frequency influences translocation speed and scaling behavior.

Contribution

It extends the iso-flux tension propagation theory to include time-dependent forces and pore oscillations, providing analytical and numerical insights into their effects on translocation dynamics.

Findings

Translocation time depends on oscillation frequency and force.

Low and high frequency limits follow established scaling laws.

Intermediate frequencies cause significant deviations in scaling behavior.

Abstract

We develop a theory for polymer translocation driven by a time-dependent force through an oscillating nanopore. To this end, we extend the iso-flux tension propagation theory (IFTP) [Sarabadani \textit{et al., J. Chem. Phys.}, 2014, \textbf{141}, 214907] for such a setup. We assume that the external driving force in the pore has a component oscillating in time, and the flickering pore is similarly described by an oscillating term in the pore friction. In addition to numerically solving the model, we derive analytical approximations that are in good agreement with the numerical simulations. Our results show that by controlling either the force or pore oscillations, the translocation process can be either sped up or slowed down depending on the frequency of the oscillations and the characteristic time scale of the process. We also show that while in the low and high frequency limits the translocation time $\tau$ follows the established scaling relation with respect to chain length $N_0$, in the intermediate frequency regime small periodic fluctuations can have drastic effects on the dynamical scaling. The results can be easily generalized for non-periodic oscillations and elucidate the role of time dependent forces and pore oscillations in driven polymer translocation.