Eur. Phys. J. E (2013) 36: 86
https://doi.org/10.1140/epje/i2013-13086-y

Regular Article

Generic instabilities in a fluid membrane coupled to a thin layer of ordered active polar fluid

Theoretical Condensed Matter Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, 700 064, Calcutta, India

^* e-mail: niladri.sarkar@saha.ac.in

Received: 18 October 2012
Accepted: 29 May 2013
Published online: 14 August 2013

Abstract

We develop an effective two-dimensional coarse-grained description for the coupled system of a planar fluid membrane anchored to a thin layer of polar ordered active fluid below. The macroscopic orientation of the active fluid layer is assumed to be perpendicular to the attached membrane. We demonstrate that activity or nonequilibrium drive of the active fluid makes such a system generically linearly unstable for either signature of a model parameter that characterises the strength of activity. Depending upon boundary conditions and within a range of the model parameters, underdamped propagating waves may be present in our model. We discuss the phenomenological significance of our results.