Regensburg 2016 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 28: Poster - Complex Fluids, Granular Matter, Glasses

DY 28.5: Poster

Dienstag, 8. März 2016, 18:15–21:00, Poster C

Many-body critical Casimir interactions in colloidal suspensions — Hendrik Hobrecht and •Alfred Hucht — Fakultät für Physik and CENIDE, Universität Duisburg-Essen, 47048 Duisburg

We study the fluctuation-induced Casimir interactions in colloidal suspensions, especially between colloids immersed in a binary liquid close to its critical demixing point. To simulate these systems, we present a highly efficient cluster Monte Carlo algorithm based on geometric symmetries of the Hamiltonian. Utilizing the principle of universality, the medium is represented by an Ising system while the colloids are areas of spins with fixed orientation. Our results for the Casimir interaction potential between two particles at the critical point in two dimensions perfectly agree with the exact predictions. However, we find that in finite systems the behavior strongly depends on whether the Z₂ symmetry of the system is broken by the particles. We present Monte Carlo results for the three-body Casimir interaction potential and take a close look onto the case of one particle in the vicinity of two adjacent particles, which can be calculated from the two-particle interaction by a conformal mapping. These results emphasize the failure of the common decomposition approach for many-particle critical Casimir interactions.

Hendrik Hobrecht and Alfred Hucht, Phys. Rev. E 92, 042315 (2015), http://dx.doi.org/10.1103/PhysRevE.92.042315