arXiv subjects

Giorgia Testolina

Publications and source records attributed to Giorgia Testolina.

3 recordsLinked to original sources

arXiv2026

Electromagnetic curvature via Jacobi-Maupertuis and beyond

In the setting of electromagnetic systems, we propose a new definition of electromagnetic Ricci curvature, naturally derived via the classical Jacobi-Maupertuis reparametrization from the recent works of Assenza [IMRN, 2024] and Assenza, Marshall Reber, Terek [Communications in Mathematical Physics, 2025]. On closed manifolds, we show that if the magnetic force is nowhere vanishing and the potential is sufficiently small in the $C^2$ norm, then this Ricci curvature is positive for energies close to the maximum value of the potential $e_0$. As a main application, under these assumptions, we extend the existence of contractible closed orbits at energy levels near $e_0$ from almost every to everywhere.

math.DG↗

arXiv2026

Relative equilibria, linear stability and electromagnetic curvature

In this paper we study the linear stability of relative equilibria in the Newtonian $n$-body problem from the viewpoint of electromagnetic systems. We first examine the effect of the ambient dimension on stability, starting from the Lagrange equilateral triangle solutions of the three-body problem in $\mathbb R^4$. We then initiate a new approach to stability based on electromagnetic curvature. In a two-dimensional model, we relate linear stability to both the Mañé critical value and to the behavior of the zero set of the electromagnetic curvature, highlighting a change in its topology at the stability threshold. This criterion is then applied to the planar $n$-body problem: in the three-body case, we recover Routh's classical criterion, and, more generally, we obtain an instability criterion for relative equilibria whose reduced linearized dynamics splits along invariant symplectic planes. These results suggest a new geometric perspective on linear stability and on questions related to Moeckel's conjecture.

math.DS↗

arXiv2025

Bifurcations of planar balanced configurations for the $n$-body problem in $\mathbb{R}^4$

Central configurations play a fundamental role in the Newtonian $n$-body problem, as they give rise to motions in which the configuration evolves while preserving its shape up to rotation and scaling. These include relative equilibria, where the configuration rigidly rotates about the center of mass and each body moves along a circular orbit. For $d\le3$, such motions originate only from planar central configurations, whereas in higher dimensions the richer structure of the orthogonal group admits new balanced configurations that can produce non-planar relative equilibria. Building on the framework introduced by Asselle, Portaluri and Fenucci [J. Fixed Point Theory App., 2022], we analyze bifurcations of planar balanced configurations in $\mathbb{R}^4$. We extend a classical variational result, which guarantees the existence of bifurcation points along trivial branches of critical points that are degenerate only at finitely many points, to the case where the trivial branch remains degenerate throughout. Applying this extension, we establish the existence of bifurcation points along the planar balanced configuration branch and derive a lower bound on their number.

math.DS↗