Invariances of Approximately Relativistic Hamiltonians and the Center-Of-Mass Theorem
197616 pages
Published in:
- Phys.Rev.D 13 (1976) 1598-1613
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Abstract: (APS)
In an earlier paper we considered a class of Lagrangians for directly interacting particles, arising from a slow-motion approximation in various special- and general-relativistic field theories. It was shown that if the Lagrangian is invariant under time and space translations this implies invariance under an additional three-parameter set of infinitesimal transformations, which leads directly to the center-of-mass theorem. This result is rederived here in a Hamiltonian formalism, in which these infinitesimal transformations are shown to be generators of a Lie symmetry group in phase space. Then we consider the problem of the most general form possible of a canonical post-Newtonian theory that is a realization of the Lie algebra of the Poincaré group to order c−2 and that arises from a theory of the usual Newtonian type with two-body interactions. It is found that in such a theory the world-line condition is satisfied to order c−2. This canonical theory encompasses all the approximately relativistic interactions, found recently by Woodcock and Havas, which follow from a Fokker-type special-relativistic variational principle for particles with direct two-body interactions. The relation of our work to various other approaches to approximately relativistic theories of interacting particles is discussed.- RELATIVITY THEORY
- TRANSFORMATION
- KINEMATICS: PHASE SPACE
- GROUP THEORY: LIE
- INVARIANCE: LORENTZ
- MOMENTUM: CONSERVATION LAW
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