Hysteresis loop area scaling exponents in DNA unzipping by a periodic force: A Langevin dynamics simulation study

TL;DR

This study uses Langevin dynamics simulations to analyze the hysteresis behavior of DNA unzipping under periodic force, revealing specific scaling exponents for the hysteresis loop area at different frequencies.

Contribution

It provides new insights into the scaling behavior of DNA unzipping hysteresis, confirming exponents consistent with previous lattice models and contrasting with shorter DNA studies.

Findings

Hysteresis loop area scales as 1/ω at high frequencies.

In low frequency, area scales as (G-G_c)^{1}ω^{1.25}.

Exponents match lattice model results, differing from shorter DNA studies.

Abstract

Using Langevin dynamics simulations, we study the hysteresis in unzipping of longer double stranded DNA chains whose ends are subjected to a time dependent periodic force with frequency $\omega$ and amplitude $G$ keeping the other end fixed. We find that the area of the hysteresis loop, $A_{loop}$, scales as $1/\omega$ at higher frequencies, whereas it scales as $(G-G_c)^{\alpha}\omega^{\beta}$ with exponents $\alpha=1$ and $\beta=1.25$ in the low frequency regime. These values are same as the exponents obtained in Monte Carlo simulation studies of a directed self avoiding walk model of a homopolymer DNA [R. Kapri, Phys. Rev. E 90, 062719 (2014)], and the block copolymer DNA [R. K. Yadav and R. Kapri, Phys. Rev. E 103, 012413 (2021)] on a square lattice, and differs from the values reported earlier using Langevin dynamics simulation studies on a much shorter DNA hairpins.