Regensburg 2007 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 26: Poster Session II

BP 26.5: Poster

Donnerstag, 29. März 2007, 17:00–19:30, Poster B

Curvature coupled diffusion of an inclusion in a fluctuating membrane — •Stefan Leitenberger, Ellen Reister-Gottfried, and Udo Seifert — II. Institut für Theoretische Physik, Universität Stuttgart, Pfaffenwaldring 57/III, 70550 Stuttgart

We analyse the lateral diffusion of an inclusion along a fluctuating membrane. The inclusion interacts with the membrane shape via the local curvature. We derive equations of motion for the membrane dynamics and the projected motion of the inclusion. With these equations and neglecting the influence of the inclusion on the membrane dynamics we calculate the diffusion coefficient of the inclusion. In order to probe the analytical results and to overcome approximations of the analytical calculations, we set up a simulation that also neglects the effects of the inclusion on the membrane dynamics. Comparing the results we find that the diffusion coefficients achieved in the simulations are smaller than the analytical ones. In the calculations it is necessary to average over all possible forces acting on the particle at each lattice site, independently of the actual particle position while the simulations correctly average the force correlations along the particle trajectory. If the diffusing particle remains close to positions on the membrane that are energetically favourable the force correlation function will be reduced compared to the situation when the particle is at some random position. The detailed investigation of the force correlation function indicates that the inclusion generally follows an energy minimum on the membrane. This explains the difference between analytical calculations and simulations.