Resumo: Kinetic roughening is a well-known instance of non-equilibrium phenomena in which spatiotemporal scale-invariance occurs. This has made it a natural generalization of equilibrium critical behavior. Thus, related concepts like the universality class, and techniques, such as the renormalization group, have provided successful theoretical frameworks to characterize and describe this type of behavior. A paradigmatic system in this context is the so-called Kardar-Parisi-Zhang (KPZ) equation, expected to describe the large-scale behavior of many far-from-equilibrium surfaces in which dynamics are not conserved. Recent theoretical and experimental results on KPZ growth show quite dramatically the degree to which universality occurs in this class. Motivated by them, we will address a number of situations in which. nevertheless, KPZ universality does not operate in the form that would be naively expected. These include systems with non-local or with anisotropic interactions, or growth of circular interfaces. Elucidation of their peculiarities will undoubtedly improve our understanding of the way in which universality needs to be generalized to this type of spatially extended, non-equilibrium systems.
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