Paper on Bifurcations of Riemann Ellipsoids accepted in the SIAM Journal on Applied Dynamical Systems.

On 29 October, a paper titled Bifurcations of Riemann Ellipsoids (arXiv link) was accepted for publication in the SIAM Journal on Applied Dynamical Systems.
The paper is authored by Fahimeh Mokhtari (VU), Jesús F. Palacián, and Patricia Yanguas from Universidad Pública de Navarra.

The paper describes how the stability of three types of Riemann ellipsoids changes by identifying the associated quasi-periodic Hamiltonian bifurcations. After suitable symplectic coordinate changes- both linear and nonlinear normal form transformations—the bifurcations responsible for these stability transitions are characterised.
Three types of bifurcations arise: Hamiltonian pitchfork, saddle–centre, and Hamiltonian–Hopf bifurcations in the four-degree-of-freedom Hamiltonian system obtained after symmetry reduction. The analysis is mainly analytical, with certain non-degeneracy conditions verified numerically.