Phase portraits of separable Hamiltonian systems

Abstract

We study some generalizations of potential Hamiltonian systems (H(x, y) = y 2 + F(x)) with one degree of freedom. In particular, we are interested in Hamiltonian systems with Hamiltonian functions of type H(x, y) = F(x) + G(y) arising in applied mechanical problems. We present an algorithm to plot the phase portrait (include the behavior at infinity) of any Hamiltonian system of type H(x, y) = F(x) +G(y), where F and G are arbitrary polynomials. We are able to give the full description in the Poincaré disk according to the graphs of F and G, extending the well-known method for the “finite”phase portrait of potential systems.