Sommaire:

A remarkable success of 20th-century Physics is the framework of statistical Physics that bridges the atomistic and macroscopic worlds. However, this framework is only limited to systems in thermal equilibrium. In reality, most systems in nature are outside equilibrium. A cup of coffee left on a table, reaches thermal equilibrium in an hour or so by releasing heat, but over longer periods it evaporates. Living matter, like bacteria, generates energy currents from burning ATP to self-organize at large scales. Such non-zero currents break time-reversal symmetry, thus constantly generating entropy. As a result, the statistics of these systems do not follow the principals of statistical Physics. In fact, at present, there is no general conceptual framework à la Gibbs-Boltzmann to describe non-equilibrium Physics from first principles. It is not even clear how to generalize the basic ideas of state variables like pressure and temperature, or thermodynamic potentials like the free energy.

An emerging idea is to build a unifying theory at a mesoscopic scale, similar to the Landau-Ginzburg theory for equilibrium fluctuations. I will discuss, how the theory of large deviations offers such an avenue by extending the idea of the Landau free energy outside equilibrium in terms of large deviation functions. This way, non-equilibrium phase transitions appear as singularities in large deviations, as in equilibrium; generic non-local response of non-equilibrium states is a simple consequence of non-local large deviation functions, and fluctuation relations are due to symmetries of large-deviations.

Many important recent advances in non-equilibrium Physics came from this large deviation approach, driven by experiments, computer simulations, and theoretical analysis of minimal models. In this talk, I will review these new ideas and illustrate them with examples from soft-condensed matter. These include anomalous tracer diffusion in single-file motion, dynamical phase transitions in stochastic processes, thermodynamic uncertainty relations, and hydrodynamics of classical and quantum transport.

Pour plus d'informations, merci de contacter Poy G.