Dynamics of active membranes with internal noiseD. Lacoste1 and A. W. C. Lau2, 3
1 Laboratoire de Physico-Chimie Théorique, UMR 7083 CNRS-ESPCI 10 rue Vauquelin, F-75231 Paris cedex 05, France
2 Department of Physics and Astronomy, University of Pennsylvania Philadelphia, PA 19104, USA
3 Department of Physics, Florida Atlantic University - Boca Raton, FL 33431, USA
received 30 September 2004; accepted in final form 14 March 2005
published online 6 April 2005
We study the time-dependent height fluctuations of an active membrane containing energy-dissipating pumps that drive the membrane out of equilibrium. Unlike previous investigations based on models that neglect either curvature couplings or random fluctuations in pump activities, our formulation explores two new models that take both of these effects into account. In the first model, the magnitude of the nonequilibrium forces generated by the pumps is allowed to fluctuate temporally. In the second model, the pumps are allowed to switch between "on" and "off" states. We compute the mean-squared displacement of a membrane point for both models, and show that they exhibit distinct dynamical behaviors from previous models, and in particular, a superdiffusive regime specifically arising from the shot noise.
87.16.-b - Subcellular structure and processes.
05.40.-a - Fluctuation phenomena, random processes, noise, and Brownian motion.
05.70.Np - Interface and surface thermodynamics.
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