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Title: Symmetries and first integrals of some differential equations of dynamics

Journal Article · · Hadronic J.; (United States)
OSTI ID:6520040

The theme of this paper is the study of the symmetry properties of some differential equations of dynamics, and of the construction of first integrals. For the time-dependent harmonic oscillator the Lewis invariant provides a quadratic function which is a constant of motion. Different derivatives are considered with a view to assigning some physical meaning to the invariant and to the function rho(t) in terms of which the invariant is expressed. Lie's theory of differential equations, which until recently has been sadly neglected in comparison with his other pioneering works, is applied to consider groups of point transformations which leave invariant the equations of motion. For the time-dependent oscillator, an eight-parameter Lie group is obtained. A five-parameter Noether sub-group leaves also the action function invariant. Some results concerning the symmetries of the Kepler problem are also reported. Dynamical symmetries, not covered by point transformations, are briefly discussed.

Research Organization:
La Trobe Univ., Victoria, Australia
OSTI ID:
6520040
Journal Information:
Hadronic J.; (United States), Vol. 2:5
Country of Publication:
United States
Language:
English