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Published Online: 04 June 1998
Accepted: May 1994
Journal of Mathematical Physics 35, 5734 (1994); https://doi.org/10.1063/1.530708
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  • Facultad de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22, Chile
A rather strong concept of symmetry is introduced in classical mechanics, in the sense that some mechanical systems can be completely characterized by the symmetry laws they obey. Accordingly, a ‘‘complete symmetry group’’ realization in mechanics must be endowed with the following two features: (1) the group acts freely and transitively on the manifold of all allowed motions of the system; (2) the given equations of motion are the only ordinary differential equations that remain invariant under the specified action of the group. This program is applied successfully to the classical Kepler problem, since the complete symmetry group for this particular system is here obtained. The importance of this result for the quantum kinematic theory of the Kepler system is emphasized.
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    this is perhaps the most exhaustive monography on this subject. See also G. W. Bluman and S. Kumei, Symmetries and Differential Equations (Springer Verlag, New York, 1989). Google Scholar
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    but such transformations fail to produce a “complete symmetry group” in the sense required here. To take a case in point, contact transformations for the classical Kepler problem were studied by J. M. Levy-Leblond, Am. J. Phys. 39, 502 (1971), but they do not yield a complete group for this particular system. Google ScholarCrossref
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    nevertheless, it is not known if this group is complete for that system. All these results on point symmetries, and perhaps some few others, have been found by means of the traditional Lie method. Moreover, much of this subject was known already to Sophus Lie himself [S. Lie, Vorlesungen über Differential-Gleichungen Mit Bekannten Infinitesimal Transformationen (B. G. Teubner, Leipzig, 1981; Google Scholar
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    however, it seems to be not so well known to most physicists. For instance, the rediscovery eighteen years ago by C. E. Wulfman and B. G. Wyborne, J. Phys. A 9, 507 (1976), that the equation of motion ẍ+ω2x = 0 has point symmetry SL(3,R) was a surprise to physicists. Google ScholarScitation
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  8. 8. One could also enlarge GL considering its improper pieces in Eq. (3), but we are not concerned with such minor details now. , Google Scholar
  9. 9. The energy is given by E = (M2−K2)/2J2. The Hamilton vector is W = (KL)−1J×M = (k/L)εn̂; Google Scholar
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    A. Bohm, Nuovo Cim. 43, A665 (1966), and references quoted therein. The O+(4) symmetry of the Kepler system sets an “age” problem that has been much investigated, owing mainly to its important role in the quantum-mechanic theory of the hydrogen atom. Even more recently, the Fock quantization of the hydrogen atom has been reformulated by means of the symmetry SO(2,n+l) of the n-dimensional Kepler problem; Google Scholar
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  18. © 1994 American Institute of Physics.