Application of the logarithmic Hamiltonian algorithm to the circular restricted three-body problem with some post-Newtonian terms

An implementation of a fourth-order symplectic algorithm to the logarithmic Hamiltonian of the Newtonian circular restricted three-body problem in an inertial frame is detailed. The logarithmic Hamiltonian algorithm produces highly accurate results, comparable to the non-logarithmic one. Its numerical performance is independent of an orbital eccentricity. However, it is not when some post-Newtonian terms are included in this problem. Although the numerical accuracy becomes somewhat poorer as the orbital eccentricity gets larger, it is still much higher than that of the non-logarithmic Hamiltonian algorithm. As a result, the present code can drastically eliminate the overestimation of Lyapunov exponents and the spurious rapid growth of fast Lyapunov indicators for high-eccentricity orbits in the Newtonian or post-Newtonian circular restricted three-body problem.