The potential energy surface and chaos in 2D Hamiltonian systems

Pumping a swing revisited: minimal model for parametric resonance via matrix products

“…For example, a particle moving where a static potential in two or more dimensions is concave everywhere (i.e. its principal curvatures-eigenvalues of the Hessian matrix of derivatives-are positive at all points on the orbit) can nevertheless exhibit chaos, notwithstanding occasional suggestions to the contrary [14][15][16], (see also [17][18][19]…”