Numerical Computation of Transverse Homoclinic Orbits for Periodic Solutions of Delay Differential Equations

SIAM Journal on Applied Dynamical Systems, Volume 22, Issue 4, Page 3093-3129, December 2023.
Abstract. We present a computational method for studying transverse homoclinic orbits for periodic solutions of delay differential equations, a phenomenon that we refer to as the Poincaré scenario. The strategy is geometric in nature and consists of viewing the connection as the zero of a nonlinear map, such that the invertibility of its Fréchet derivative implies the transversality of the intersection. The map is defined by a projected boundary value problem (BVP), with boundary conditions in the (finite dimensional) unstable and (infinite dimensional) stable manifolds of the periodic orbit. The parameterization method is used to compute the unstable manifold, and the BVP is solved using a discrete time dynamical system approach (defined via the method of steps) and Chebyshev series expansions. We illustrate this technique by computing transverse homoclinic orbits in the cubic Ikeda and Mackey–Glass systems.