Berlin 2008 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 20: POSTERS Driven Soft Matter

CPP 20.19: Poster

Mittwoch, 27. Februar 2008, 16:00–18:30, Poster A

On multiplicative forcing effects in the Cahn-Hilliard model — •Christian Feller, Alexei Krekhov, and Walter Zimmermann — Theoretische Physik I, Universität Bayreuth, 95440 Bayreuth, Germany

Phase separation in the presence of a spatially periodic temperature modulation has been investigated theoretically. The linear stability analysis of the homogeneous basic state of the Cahn-Hilliard model with periodic modulation G cos(Q x) of the control parameter has been performed.
The threshold for the onset of the bifurcation has been determined as function of the modulation amplitude G and the modulation wave number Q. For harmonic and subharmonic solutions with respect to the modulation of the control parameter one obtains different thresholds for the bifurcation from the basic state. The threshold for the harmonic solutions is always lower. Beyond the threshold there exists a discrete set of periodic solutions characterized by the wave number Q/m (with integer m) which become stable only beyond a certain second threshold.
It has been found that in the two dimensional case additional longitudinal perturbations do not influence the bifurcation diagram obtained for one dimension. Numerical simulations of phase separation dynamics in a quenched system in two dimensions are compared with the results of linear stability analysis.