Regensburg 2004 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 24: Dynamic Instabilities in Biophysics

DY 24.2: Vortrag

Dienstag, 9. März 2004, 15:00–15:15, H2

Barrier crossing of semiflexible polymers — •Pavel Kraikivski, Jan Kierfeld, and Reinhard Lipowsky — MPI für Kolloid- und Grenzflächenforschung, 14424 Potsdam

We study the motion of semiflexible polymers in double-well potentials. We calculate shape, energy, and effective diffusion constant of kink excitations, and in particular their dependence on the bending rigidity of the semiflexible polymer. For symmetric potentials, the kink motion is purely diffusive whereas kink motion becomes directed in the presence of a driving force on the polymer. We determine the average velocity of the semiflexible polymer based on the kink dynamics. The Kramers escape over the potential barriers proceeds by nucleation and diffusive motion of kink-antikink pairs, the relaxation to the straight configuration by annihilation of kink-antikink pairs. Our results apply to the activated motion of biopolymers such as DNA and actin filaments or synthetic polyelectrolytes on structured substrates.