Current fluctuations across a nanopore

TL;DR

This paper investigates the frequency-dependent current fluctuations in nanopores using analytical models and simulations, providing simplified expressions for practical analysis and validating them with Langevin dynamics simulations.

Contribution

It introduces an analytical expression for current fluctuations in nanopores based on a stochastic Nernst-Planck model, incorporating channel geometry and validated through simulations.

Findings

Derived a complex analytical expression for current fluctuations.

Proposed simplified approximations for practical use.

Validated analytical results with Langevin dynamics simulations.

Abstract

The frequency-dependent spectrum of current fluctuations through nano-scale channels is studied using analytical and computational techniques. Using a stochastic Nernst-Planck description and neglecting the interactions between the ions inside the channel, an expression is derived for the current fluctuations, assuming that the geometry of the channel can be incorporated through the lower limits for various wave-vector modes. Since the resulting expression turns out to be quite complex, a number of further approximations are discussed such that relatively simple expressions can be used for practical purposes. The analytical results are validated using Langevin dynamics simulations.