Seifert, UdoLanger, Stephen A.2011-12-212016-03-312011-12-212016-03-311993364608706http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-69668http://elib.uni-stuttgart.de/handle/11682/7823http://dx.doi.org/10.18419/opus-7806We determine the dispersion relation for a fluid bilayer membrane, taking into account the coupling between bending and the local density of the two monolayers. Apart from important corrections to the conventional bending mode, we obtain a second slow mode which is essentially a fluctuation in the density difference of the two monolayers, damped by inter-monolayer friction. Estimates for a stack of membranes show reasonable agreement with a recent spin-echo study of membrane undulations.eninfo:eu-repo/semantics/openAccessMembran , Diffusion , Grenzfläche530article