Stefano Zapperi

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The study of critical phenomena and universal power laws has been one of the central advances in statistical mechanics during the second half of the past century, explaining traditional thermodynamic critical points1, avalanche behaviour near depinning transitions2,3 and a wide variety of other phenomena4. Scaling, universality and the renormalization group(More)
We present generic scaling laws relating spreading critical exponents and avalanche exponents (in the sense of self-organized criticality) in general systems with absorbing states. Using these scaling laws we present a collection of the state-of-the-art exponents for directed percolation, dynamical percolation, and other universality classes. This(More)
We present a pedagogical introduction to self-organized criticality (SOC), unraveling its connections with nonequilibrium phase transitions. There are several paths from a conventional critical point to SOC. They begin with an absorbing-state phase transition (directed percolation is a familiar example), and impose supervision or driving on the system; two(More)
8 Cerling et al. reply — Köhler et al. suggest that phenomena other than floral change may be involved in the late Miocene global vegetation change, such as monsoonal dynamics or unnamed “other factors”. Citing evidence from Spain and Pakistan, they do not believe that there is necessarily a synchronicity or a causal link between faunal and vegetation(More)
The identification of cancer stem cells in vivo and in vitro relies on specific surface markers that should allow to sort cancer cells in phenotypically distinct subpopulations. Experiments report that sorted cancer cell populations after some time tend to express again all the original markers, leading to the hypothesis of phenotypic switching, according(More)
We explore, in the mean-field approximation, robustness with respect to dissipation of self-organized criticality in sandpile models. To this end, we generalize a recently introduced self-organized branching process, and show that the model self-organizes not into a critical state but rather into a subcritical state: when dissipation is present, the(More)
We derive an equation of motion for the dynamics of a ferromagnetic domain wall driven by an external magnetic field through a disordered medium, and we study the associated depinning transition. The long-range dipolar interactions set the upper critical dimension to be dc ­ 3, so we suggest that mean-field exponents describe the Barkhausen effect for(More)
We introduce a systematic method for extracting multivariable universal scaling functions and critical exponents from data. We exemplify our insights by analyzing simulations of avalanches in an interface using simulations from a driven quenched Kardar-Parisi-Zhang (qKPZ) equation. We fully characterize the spatial structure of these avalanches--we report(More)
Under stress, many crystalline materials exhibit irreversible plastic deformation caused by the motion of lattice dislocations. In plastically deformed microcrystals, internal dislocation avalanches lead to jumps in the stress-strain curves (strain bursts), whereas in macroscopic samples plasticity appears as a smooth process. By combining three-dimensional(More)