Quasi-stationary states in particle systems with power law interactions
| Quand ? |
Le 08/06/2015, de 11:00 à 12:30 |
|---|---|
| Où ? | Centre Blaise Pascal |
| Participants |
Michael Joyce |
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Quasi-stationary states” are very long lived non-equilibrium stationary states which have been observed in numerous classical many body systems with long-range interactions. In the first part of my talk I will review the nature of these states - of which the most notable example are galaxies - and their theoretical interpretation within the framework of the Vlasov equation. In the second part I will address the question of how their existence is tied to the nature of the underlying interaction, and in particular to its properties at large and small scales. Two quite different approaches to the question lead to the conclusion, born out by numerical study, that the existence of these states is a robust property only for interactions for which the pair force is non-integrable at large separation. This motivates a natural classification of interactions into “"dynamically" long/short range which is distinct from the usual thermodynamic classification.