Thermodynamic Blocking in Self-Gravitating Systems

Building upon a thermodynamic formalism, we show that one-dimensional self-gravitating systems in hydrostatic equilibrium with a uniform density are in maximal entropy states when submitted to adiabatic perturbations, i.e., perturbations that maintain the hydrostatic equilibrium. We also show that the same result holds for three-dimensional spherical systems when submitted to spherically symmetric adiabatic perturbations. We coin this phenomenon “thermodynamic blocking”, given its similarity to the more general “kinetic blocking”. This result underlines the importance of the thermodynamic formalism, which proves useful when kinetic equations break down.