Centre de Physique Théorique


Mercredi 11 décembre 2019

16h00 – 17h00, Amphi 5 du CPT

First-passage time of non markovian random walks

Nicolas Levernier (IUSTI)

The computation of the encounter time of particles is a key question in many context, as this time quantifies the reactivity rate for diffusion-limited processes. In the case of markovian random walks, such as brownian motion, some analytic results can be obtained. But in the case of non-markovian processes, much fewer results do exist, although "non-markov is the rule and markov is the exception" (Van Kampen). In this talk I will present a formalism we have developed to deal with non-markovian random walks and show its application to Fractional Brownian Motion, a paradigmatic example of highly-correlated process.

In a second part of my talk, I will briefly present recent results I got during my postdoc. I will show how chaotic motion can arise in an extended active gel layer, typically describing cortical cytoskeleton. This result questions the usual description of the cortex as a thin layer, as such a description cannot describe this instability.