title: The Power Spectrum of Ionic Nanopore Currents: The Role of Ion Correlations.
abstract: We calculate the power spectrum of electric-field-driven ion transport through nanometer-scale membrane pores using both linearized mean-field theory and Langevin dynamics simulations. Remarkably, the linearized mean-field theory predicts a plateau in the power spectral density at low frequency ω, which is confirmed by the simulations at low ion concentration. At high ion concentration, however, the power spectral density follows a power law that is reminiscent of the 1/ω(α) dependence found experimentally at low frequency. On the basis of simulations with and without ion-ion interactions, we attribute the low-frequency power-law dependence to ion-ion correlations. We show that neither a static surface charge density, nor an increased pore length, nor an increased ion valency have a significant effect on the shape of the power spectral density at low frequency.
authors.affiliation: Rudolf Peierls Centre for Theoretical Physics, Oxford University , Oxford, OX13NP, United Kingdom.
authors.forename: Mira
authors.initials: M
authors.lastname: Zorkot
authors.affiliation: Rudolf Peierls Centre for Theoretical Physics, Oxford University , Oxford, OX13NP, United Kingdom.
authors.forename: Ramin
authors.initials: R
authors.lastname: Golestanian
authors.affiliation: Rudolf Peierls Centre for Theoretical Physics, Oxford University , Oxford, OX13NP, United Kingdom.
authors.forename: Douwe Jan
authors.initials: DJ
authors.lastname: Bonthuis
keywords: 1/f noise; Langevin simulations; Nanopores; ion transport; mean-field theory; power spectral density