We describe and analyze a bistable reaction-diffusion (RD) model for two interconverting chemical species that exhibits a phenomenon of wave-pinning: a wave of activation of one of the species is initiated at one end of the domain, moves into the domain, decelerates, and eventually stops inside the domain, forming a stationary front. The second ("inactive") species is depleted in this process. ...

We review the most striking experimental results on aging in a variety of disordered systems, which reveal similar features but also important differences. We argue that a generic model that reproduce many of these features is that of pinned defects in a disordered environment, hoping between different metastable states. The fact that energy barriers grow with the size of the reconforming regio...

Magnetic skyrmions are topological quasiparticles that can be formed in systems with particular magnetic interactions. Here, the authors study dense arrays of a thin film heterostructure, showing form liquid, properties which depend strongly on size and density skyrmions. The presence pinning sites alters behavior skyrmion liquid compared to typical liquids, but these shown have narrow energy d...