Anisotropic Hydrodynamic Mean-Field Theory for Semiflexible Polymers under Tension

TL;DR

This paper develops an anisotropic mean-field theory to accurately describe the dynamics of semiflexible polymers under intermediate tension, capturing hydrodynamic interactions, stiffness, and fluctuations without extra fitting.

Contribution

It introduces a novel anisotropic mean-field approach that precisely models semiflexible polymer dynamics under tension, validated against simulations and experiments.

Findings

Accurately reproduces equilibrium averages of stretched polymers.

Matches Brownian hydrodynamics simulations and optical tweezer data.

Effective across a broad range of intermediate tensions.

Abstract

We introduce an anisotropic mean-field approach for the dynamics of semiflexible polymers under intermediate tension, the force range where a chain is partially extended but not in the asymptotic regime of a nearly straight contour. The theory is designed to exactly reproduce the lowest order equilibrium averages of a stretched polymer, and treats the full complexity of the problem: the resulting dynamics include the coupled effects of long-range hydrodynamic interactions, backbone stiffness, and large-scale polymer contour fluctuations. Validated by Brownian hydrodynamics simulations and comparison to optical tweezer measurements on stretched DNA, the theory is highly accurate in the intermediate tension regime over a broad dynamical range, without the need for additional dynamic fitting parameters.