Nonequilibrium First-order Transition Research Articles

Macroscopic yielding in jammed solids is accompanied by a nonequilibrium first-order transition in particle trajectories.

We use computer simulations to analyze the yielding transition during large-amplitude oscillatory shear of a simple model for soft jammed solids. Simultaneous analysis of global mechanical response and particle-scale motion demonstrates that macroscopic yielding, revealed by a smooth crossover in mechanical properties, is accompanied by a sudden change in the particle dynamics, which evolves from nondiffusive motion to irreversible diffusion as the amplitude of the shear is increased. We provide numerical evidence that this sharp change corresponds to a nonequilibrium first-order dynamic phase transition, thus establishing the existence of a well-defined microscopic dynamic signature of the yielding transition in amorphous materials in oscillatory shear.

Role of Diffusion in the Shaping of the High-Absorption State in a Resonatorless Exciton Bistable System

We present a unified approach to description of all the stages of shaping of a highabsorption state in a resonatorless exciton bistable system, as a nonequilibrium first-order transition. The velocity of switching wave front and thickness of interface between phases are determined within the quick switching wave approximation. The size distribution functions of subcritical and supercritical nuclei and asymptotic expression for nucleus radius were obtained.