Testing the Gallavotti-Cohen fluctuation theorem on the solar photosphere.

In statistical mechanics, the steady-state fluctuation theorem of Gallavotti and Cohen (1995) describes some symmetry features of the entropy production rate (or of a variable related to phase space contraction rate) and its fluctuations in non-equilibrium stationary states. Here, we present a test of the validity of such a theorem on the turbulent solar convection in quiet solar regions, using as a proxy of the phase-space contraction rate the vertical heat flux at the solar photosphere, obtained from high-resolution data acquired through the Interferometric BIdimensional Spectropolarimeter at the Dunn Solar Telescope.