title: Hybrid simulations of lateral diffusion in fluctuating membranes.
abstract: In this paper we introduce a method to simulate lateral diffusion of inclusions in a fluctuating membrane. The regarded systems are governed by two dynamic processes: the height fluctuations of the membrane and the diffusion of the inclusion along the membrane. While membrane fluctuations can be expressed in terms of a dynamic equation which follows from the Helfrich Hamiltonian, the dynamics of the diffusing particle is described by a Langevin or Smoluchowski equation. In the latter equations, the curvature of the surface needs to be accounted for, which makes particle diffusion a function of membrane fluctuations. In our scheme these coupled dynamic equations, the membrane equation and the Langevin equation for the particle, are numerically integrated to simulate diffusion in a membrane. The simulations are used to study the ratio of the diffusion coefficient projected on a flat plane and the intramembrane diffusion coefficient for the case of free diffusion. We compare our results with recent analytical results that employ a preaveraging approximation and analyze the validity of this approximation. A detailed simulation study of the relevant correlation functions reveals a surprisingly large range where the approximation is applicable.
authors.affiliation: II. Institut für Theoretische Physik, Universität Stuttgart, 70550 Stuttgart, Germany. reister@theo2.physik.uni-stuttgart.de
authors.forename: Ellen
authors.initials: E
authors.lastname: Reister-Gottfried
authors.forename: Stefan M
authors.initials: SM
authors.lastname: Leitenberger
authors.forename: Udo
authors.initials: U
authors.lastname: Seifert
mesh_terms: D001703:Biophysics / Q000379:methods*; D003198:Computer Simulation; D004058:Diffusion; D005583:Fourier Analysis; D008560:Membrane Fluidity; D008566:Membranes / Q000737:chemistry*; D015233:Models, Statistical; D008962:Models, Theoretical; D012984:Software; D013997:Time Factors