title: Exact invariants for a class of three-dimensional time-dependent classical hamiltonians
abstract: An exact invariant is derived for three-dimensional Hamiltonian systems of N particles confined within a general velocity-independent potential. The invariant is found to contain a time-dependent function f(2)(t), embodying a solution of a third-order differential equation whose coefficients depend on the explicitly known trajectories of the particle ensemble. Our result is applied to a one-dimensional time-dependent nonlinear oscillator and to a system of Coulomb interacting particles in a time-dependent quadratic external potential.
authors.affiliation: Gesellschaft fur Schwerionenforschung (GSI), Planckstrasse 1, 64291 Darmstadt, Germany.
authors.initials: J
authors.lastname: Struckmeier
authors.initials: C
authors.lastname: Riedel