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CPP: Chemische Physik und Polymerphysik

CPP 8: SYMPOSIUM Nonequilibrium Phenomena in Soft-Condensed Matter

CPP 8.8: Talk

Tuesday, March 28, 2006, 16:00–16:15, ZEU Lich

Nonequilibrium subdiffusion of a Brownian particle in a quasicrystalline potential — •Michael Schmiedeberg and Holger Stark — Universität Konstanz, Fachbereich Physik, D-78457 Konstanz

We study the motion of a single colloidal particle in an optical lattice with two-dimensional quasicrystalline symmetry. From Brownian-dynamics simulations we find that initially the particle exhibits subdiffusional motion over several decades in time until it crosses over to pure diffusion in the long-time limit. We demonstrate that the subdiffusion is due to a temporally extended relaxation process towards thermal equilibrium where the particle then enters the diffusive regime. The duration of the transient subdiffusion increases for decreasing temperature. We observe a similar behavior for the motion of particles in random potentials which demonstrates that quasicrystalline systems are useful for studying aspects of disordered systems.