New vistas on the Laplace-Runge-Lenz vector

Abstract

Scalar, vector and tensor conserved quantities are essential tools in solving different problems in physics and complex, nonlinear differential equations in mathematics. In many guises they enter our understanding of nature: charge, lepton, baryon numbers conservation accompanied with constant energy, linear or angular total momenta and the conservation of energy-momentum/angular momentum tensors in field theories due to Noether theorem which is based on the translational and Lorentz symmetry of the Lagrangians. One of the oldest discovered conserved quantities is the Laplace-Runge-Lenz vector for the $1/r$-potential. Its different aspects have been discussed many times in the literature. But explicit generalisations to other spherically symmetric potentials are still rare. Here, we attempt to fill this gap by constructing explicit examples of a conserved vector perpendicular to the angular momentum for a class of phenomenologically relevant potentials. Hereby, we maintain the nomenclature and keep calling these constant vectors Laplace-Runge-Lenz vectors.