Criteria for minimal model of driven polymer translocation

TL;DR

This paper investigates the minimal conditions needed for an accurate model of driven polymer translocation, emphasizing the importance of fluctuations and proposing a simplified model that aligns with detailed simulations.

Contribution

It identifies the critical role of fluctuations in translocation dynamics and establishes criteria for a minimal yet accurate model of driven polymer translocation.

Findings

Fluctuations significantly influence the translocation exponent .

Incomplete models excluding fluctuations contradict full model results.

A minimal model with dynamics excluded can still replicate key behaviors.

Abstract

While the characteristics of the driven translocation for asymptotically long polymers are well understood, this is not the case for finite-sized polymers, which are relevant for real-world experiments and simulation studies. Most notably, the behavior of the exponent $\alpha$, which describes the scaling of the translocation time with polymer length, when the driving force $f_p$ in the pore is changed, is under debate. By Langevin dynamics simulations of regular and modified translocation models using the freely-jointed-chain polymer model we find that a previously reported incomplete model, where the {\it trans} side and fluctuations were excluded, gives rise to characteristics that are in stark contradiction with those of the complete model, for which $\alpha$ increases with $f_p$. Our results suggest that contribution due to fluctuations is important. We construct a minimal model where dynamics is completely excluded to show that close alignment with a full translocation model can be achieved. Our findings set very stringent requirements for a minimal model that is supposed to describe the driven polymer translocation correctly.