Annette Zippelius

SPIN-GLASS AND ANTIFERROMAGNET CRITICAL BEHAVIOR IN A DILUTED FCC ANTIFERROMAGNET

We report on a Monte Carlo study of a diluted Ising antiferromagnet on a fcc lattice. This is a typical model example of a highly frustrated antiferromagnet, and we ask, whether sufficient random dilution of spins does produce a spin glass phase. Our data strongly indicate the existence of a spin glass transition for spin--concentration

Dynamics of 2D anisotropic solids, smectics and nematics

p 0.85

A study of short-range spin glasses

, which becomes continuous in the range

Relaxational dynamics of the Edwards-Anderson model and the mean-field theory of spin-glasses

0.85>p>0.75

Pattern Selection in Rayleigh-Bénard Convection near Threshold

. Finite size scaling is employed to obtain critical exponents. We compare our results with experimental systems as diluted frustrated antiferromagnets as

Dynamic Theory of the Spin Glass Phase

{\rm Zn_{1-p}Mn_{p}Te}

Dynamics of defects in Rayleigh-Bénard convection

.

Disappearance of stable convection between free-slip boundaries

Abstract In this research we study the critical dynamics of anisotropic layers in the various transition and crossover regimes associated with a defect unbinding picture of the melting process. We derive dynamic equations of motion for anisotropic solids, smectics and nematics, in the presence of defects and predict the critical behavior of various transport coefficients. The theory is applicable to two-dimensional layers of freely suspended liquid crystals, on which dynamic light-scattering experiments can be performed to test the predictions of the theory.

Velocity-autocorrelation spectrum of simple classical liquids

Spatial fluctuations in spin glasses are studied by an expansion around the dynamic mean field theory. We discuss the properties of the low temperature phase, in particular the stability and consistency of mean field theory and identify the most divergent fluctuations and the resulting special dimensionalities of the model. The dynamic critical behaviour is studied within an e expansion around the upper critical dimension du=6.