The role of inertia and coarse-graining on the transverse modes of lipid bilayers

Georg-August-Universität, Institut für theoretische Physik - Friedrich-Hund-Platz 1, 37077 Göttingen, Germany

^a mmueller@theorie.physik.uni-goettingen.de

Received: 13 December 2011
Accepted: 27 February 2012

Abstract

We determine the transverse dispersion relations of a lipid bilayer by generalizing the Seifert-Langer theory to include the bilayer's inertia and its surface tension. Thereby we extend the applicability of the original theory to computer simulations of lipid bilayers with and without solvent, as well as to simulations with and without momentum conservation. We calculate the asymptotic dispersion relations and identify conditions under which propagating modes occur. The theory is compared with simulations of a coarse-grained, solvent-free model, where we extract the transverse dispersion relations by fitting the intermediate scattering function of bilayer undulations. An estimate of the intermonolayer friction is obtained and compared with the result of a Green-Kubo relation.