title: Deviations from linear theory for fluctuations below the supercritical primary bifurcation to electroconvection
abstract: Over two decades ago it was predicted that nonlinear interactions between thermally driven fluctuations in dissipative nonlinear nonequilibrium systems lead to deviations from mean-field theory. Here we report experimental observations of such deviations as a supercritical primary bifurcation is approached. We measured the mean-square director-angle fluctuations <straight theta(2)> below the bifurcation to electroconvection of two different nematic liquid crystals. For epsilon(mf) identical withV2/V(2)(c,mf)-1 less, similar-0.1 ( V is the applied voltage) we find <straight theta(2)> approximately |epsilon(mf)|(-gamma) with gamma given by linear theory (LT). Closer to the bifurcation there are deviations from LT with a smaller gamma and with V(2)(c)>V(2)(c,mf).
authors.affiliation: Department of Physics and iQUEST, University of California, Santa Barbara, California 93106, USA.
authors.initials: MA
authors.lastname: Scherer
authors.initials: G
authors.lastname: Ahlers
authors.initials: F
authors.lastname: Horner
authors.initials: I
authors.lastname: Rehberg