Séminaire du LPTMS: Giacomo Gradenigo

Effective thermodynamics for a driven athermal system with dry friction

Which are the situations where an effective thermodynamic theory works even in the lack of thermal equilibrium? Which is the meaning of « temperature » for an out-of-equilibrium system?

I present here the study of a driven athermal system, i.e. a one-dimensional chain of masses connected by harmonic springs and subject to Coulomb dry friction, where answers to the above questions can be provided. Our main result is the evidence that the configuration space of our system is visited under the unfluence of an external driving in an equilibrium-like manner: configurations are sampled according to their energy with a Boltzmann-like probability even in presence of a dissipative dynamics.

This evidence is obtained by comparing the exact calculation of the partition function, obtained by means of a transfer matrix approach, to numerical simulations of the driven dissipative dynamics. Interestingly enough, the existence of a critical point at infinite effective temperature is pointed out.

I conclude presenting different lines along which the spring-block model here introduced can be exploited to investigate the scope of validy of equilibrium statistical mechanics for a driven athermal systems.