title: Diffusion of a particle quadratically coupled to a thermally fluctuating field.
abstract: We study the diffusion of a Brownian particle quadratically coupled to a thermally fluctuating field. In the weak-coupling limit, a path-integral formulation allows us to compute the effective diffusion coefficient in the cases of an active particle, which tends to suppress field fluctuations, and of a passive particle, which only undergoes field fluctuations. We show that the behavior is similar to what was previously found for a linear coupling: an active particle is always slowed down, whereas a passive particle is slowed down in a slow field and accelerated in a fast field. Numerical simulations show a good agreement with the analytical calculations. The examples of a membrane protein coupled to the curvature or composition of the membrane are discussed, with a focus on the room for anomalous diffusion.
authors.affiliation: Institut Jean Le Rond d'Alembert, CNRS and UPMC, Université Paris 6, UMR 7190, F-75005 Paris, France. vincent.demery@polytechnique.edu
authors.forename: Vincent
authors.initials: V
authors.lastname: Démery
mesh_terms: D003198:Computer Simulation; D004058:Diffusion; D008565:Membrane Proteins / Q000737:chemistry* / Q000648:ultrastructure*; D008956:Models, Chemical; D008958:Models, Molecular; D011487:Protein Conformation; D013696:Temperature
chemical_list: D008565:Membrane Proteins