Dynamics of active membranes with internal noise

TL;DR

This paper investigates the complex dynamics of active membranes influenced by internal noise, introducing two novel models that incorporate fluctuating pump forces and switching states, revealing superdiffusive behaviors not seen in earlier models.

Contribution

The study presents two new models of active membranes that include both curvature effects and internal noise, advancing understanding of membrane fluctuations under nonequilibrium conditions.

Findings

Membranes exhibit superdiffusive behavior due to shot noise.

Fluctuating pump forces lead to distinct dynamical regimes.

Switching pump states significantly alter membrane fluctuation dynamics.

Abstract

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.