title: Phase transitions and marginal ensemble equivalence for freely evolving flows on a rotating sphere.
abstract: The large-scale circulation of planetary atmospheres such as that of the Earth is traditionally thought of in a dynamical framework. Here we apply the statistical mechanics theory of turbulent flows to a simplified model of the global atmosphere, the quasigeostrophic model, leading to nontrivial equilibria. Depending on a few global parameters, the structure of the flow may be either a solid-body rotation (zonal flow) or a dipole. A second-order phase transition occurs between these two phases, with associated spontaneous symmetry breaking in the dipole phase. This model allows us to go beyond the general theory of marginal ensemble equivalence through the notion of Goldstone modes.
authors.affiliation: Service de Physique de l'Etat Condensé, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Saclay, Gif-sur-Yvette, France. corentin.herbert@lsce.ipsl.fr
authors.forename: C
authors.initials: C
authors.lastname: Herbert
authors.forename: B
authors.initials: B
authors.lastname: Dubrulle
authors.forename: P H
authors.initials: PH
authors.lastname: Chavanis
authors.forename: D
authors.initials: D
authors.lastname: Paillard