The Hatano-Sasa equality: transitions between steady states in a granular gas.

Anne Mounier (1) , Antoine Naert (1)

1 Phys-ENS - Laboratoire de Physique de l'ENS Lyon

An experimental study is presented, about transitions between Non-Equilibrium Steady States (NESS) in a dissipative medium. The core device is a small rotating blade that imposes cycles of increasing and decreasing forcings to a granular gas, shaken independently. The velocity of this blade is measured, subject to the transitions imposed by the periodic torque variation. \\ The Hatano-Sasa equality, that generalises the second principle of thermodynamics to NESS, is verified with a high accuracy (a few $10^{-3}$), at different variation rates. \\ Besides, it is observed that the fluctuating velocity at fixed forcing follows a generalised Gumbel distribution. A rough evaluation of the mean free path in the granular gas suggests that it might be a correlated system, at least partially.

Domaines: Physique Générale [physics.gen-ph]

Anne Mounier, Antoine Naert. The Hatano-Sasa equality: transitions between steady states in a granular gas.. 2012. ⟨ensl-00724058v1⟩