The butterfly effect, introduced about half century ago by E. Lorenz, is now part of the
folklore of chaos and of the pop culture.
We show how for the understanding of a realistic scenario in fully developed turbulence,
one must to go beyond the pure mathematical study of infinitesimal perturbations of the Lyapunov exponent.
In particular it is necessary to take into account:
a)...
The study of thermalisation in isolated systems was pioneered by Fermi-Pasta-Ulam-Tsingou (FPUT). In this talk I will present a new avenue towards the understanding of thermalisation, the presence of a power-law in the Fourier energy spectrum. A universal scaling exponent is obtained by mapping the FPUT model onto a pair of Burgers equations. Energy is transferred to higher Fourier modes like...
We formulate coarse-grained dynamics and irreversibility from an observer-centered perspective within nonequilibrium statistical mechanics. Here, an observer is specified by a resolved subspace of observables, which determines the associated relevant ensemble, unresolved degrees of freedom, noise, and memory.
We analyze how different choices of observer modify the reduced dynamics and compare...
Fluctuation-responce relations (FRRs), or fluctuation-dissipation theorems (FDTs), are an important tool for understanding and predicting the response of physical systems to external perturbations. They come in different kinds and flavors. Thus, in equilibrium, the linear FDT of the first kind connects the linear response of a system to an external perturbation with properties of spontaneous...
