Year: 2017
Type: article
Abstract: We use Newtonian and overdamped Langevin dynamics to study long flexible polymers dragged by an external force at a constant velocity $v$. The work $W$ performed by that force depends on the initial state of the polymer and the details of the process. The Jarzynski equality can be used to relate the nonequilibrium work distribution $P(W)$ obtained from repeated experiments to the equilibrium free energy difference $\mathrm{\ensuremath{\Delta}}F$ between the initial and final states. We use the power law dependence of the geometrical and dynamical characteristics of the polymer on the number of monomers $N$ to suggest the existence of a critical velocity ${v}_{c}(N)$, such that for $v<{v}_{c}$ the reconstruction of $\mathrm{\ensuremath{\Delta}}F$ is an easy task, while for $v$ significantly exceeding ${v}_{c}$ it becomes practically impossible. We demonstrate the existence of such ${v}_{c}$ analytically for an ideal polymer in free space and numerically for a polymer which is being dragged away from a repulsive wall. Our results suggest that the distribution of the dissipated work ${W}_{\mathrm{d}}=W\ensuremath{-}\mathrm{\ensuremath{\Delta}}F$ in properly scaled variables approaches a limiting shape for large $N$.
Source: Physical review. E
Authors: Raz Halifa Levi, Yacov Kantor
Institution: Tel Aviv University
Language: English
Subfield: Statistical and Nonlinear Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funder: Israel Science Foundation
Award: G4869653067
OpenAlex ID: W2608087779