Translocation through environments with time dependent mobility

TL;DR

This paper investigates how time-dependent environmental mobility affects particle and polymer translocation times, providing analytical solutions and exploring frequency response behaviors in oscillating confinement scenarios.

Contribution

It introduces a general framework for analyzing frequency-dependent translocation times with time-varying mobility, including exact solutions for specific cases and applications to polymer translocation.

Findings

Exact expressions for translocation gain in two-state confinement.

Good agreement between theory and simulations for small polymers at low frequencies.

Deviations observed at longer lengths and higher frequencies.

Abstract

We consider single particle and polymer translocation where the frictional properties experienced from the environment are changing in time. This work is motivated by the interesting frequency responsive behaviour observed when a polymer is passing through a pore with an oscillating width. In order to explain this better we construct general diffusive and non-diffusive frequency response of the gain in translocation time for a single particle in changing environments and look at some specific variations. For two state confinement, where the particle either has constant drift velocity or is stationary, we find exact expressions for both the diffusive and non-diffusive gain. We then apply this approach to polymer translocation under constant forcing through a pore with a sinusoidally varying width. We find good agreement for small polymers at low frequency oscillation with deviations occurring at longer lengths and higher frequencies. Unlike periodic forcing of a single particle at constant mobility, constant forcing with time dependent mobility is amenable to exact solution through manipulation of the Fokker-Planck equation.