Séminaire de groupe
Critical Behaviours in Contagion Dynamics 
Lucas Boettcher 
Computational Physics for Engeneering Materials, ETH Zurich (Suisse) 
jeudi 07 décembre 2017 , 10h25 
Salle de séminaire du groupe de Physique Statistique 
Failure, damage spread and recovery crucially underlie many networked systems ranging from transportation structures to the human body. Here we study the interplay between spontaneous damage, induced failure and recovery in networks. In our model the network's components follow three realistic processes that capture these features: (i) spontaneous failure of a component independent of the neighborhood (internal failure), (ii) failure induced by failed neighboring nodes (external failure) and (iii) spontaneous recovery of a component. We identify a metastable domain in the global network phase diagram spanned by the model's control parameters where dramatic hysteresis effects and random switching between two coexisting states are observed. This dynamics depends on the characteristic link length of the embedded system. For the Euclidean lattice in particular, hysteresis and switching only occur in an extremely narrow region of the parameter space compared to random networks. We develop a unifying theory which links the dynamics of our model to contact processes and cusp catastrophe manifolds. 
