LPTMS PhD Proposal: Non stationary avalanches in disordered systems

Responsable: Alberto ROSSO 01 69 15 31 79

In many macroscopic systems the response to a constant energy input can be strongly non-linear: stress slowly accumulates over time up to a sudden and unpredictable energy release is induced by an extended reorganisations called avalanches. Economical crisis, earthquakes or epidemic outbreaks are examples of avalanche dynamics. Also the intermittent flow of soft materials, like mayonnaise or foams, can be understood in terms of avalanches. For almost 20 years, there have been many attempts to understand avalanches in the framework of critical and collective phenomena. An important result has been to show that avalanches display universal statistics. However we now know that the physics behind these latter phenomena is much richer than their equilibrium counterpart. In particular avalanches have a strong memory of the story of the material. As remarquable examples one can cite the aftershocks after an earthquake or the occurrence of a macroscopic failure in well aged materials. In this thesis we will focus on avalanches produced using non-stationary protocols in connection with experimental observations and using the tools developed for disordered systems.