Nonequilibrium heat flows through a nanorod sliding across a surface.

The temperature-ramped irreversible Langevin equation [A. V. Popov and R.

Dynamics of tracer particles in gel-like media.

Our previously proposed theory of kinetic arrest and activated barrier hopping in binary mixtures of hard and sticky spheres is applied to the problem of repulsive particle tracer diffusion. For a dynamically frozen matrix, a tracer kinetic arrest diagram is determined using a simplified version of ideal mode coupling theory. The matrix particles cluster more with increasing degree of attraction, resulting in extra free volume for tracer motion that shifts the onset of localization to higher volume fractions.

Cooperative activated dynamics in dense mixtures of hard and sticky spheres.

The coupled activated dynamics in dense mixtures of repulsive and sticky hard spheres is studied using stochastic nonlinear Langevin equation theory. The effective free energy surface, barriers, saddle point trajectories, and mean first passage times depend in a rich manner on mixture composition, (high) total volume fraction, and attractive interaction strength. In general, there are three types of saddle point trajectories or relaxation pathways: a pure sticky or pure repulsive particle displacement keeping the other species localized, and a cooperative motion involving repulsive and attractive particle displacements.

Theory of gelation, vitrification, and activated barrier hopping in mixtures of hard and sticky spheres.

Naive mode coupling theory (NMCT) and the nonlinear stochastic Langevin equation theory of activated dynamics have been generalized to mixtures of spherical particles. Two types of ideal nonergodicity transitions are predicted corresponding to localization of both, or only one, species. The NMCT transition signals a dynamical crossover to activated barrier hopping dynamics.