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Full-Text Articles in Physics
Gauge Theories Of General Relativity, James Thomas Wheeler
Gauge Theories Of General Relativity, James Thomas Wheeler
James Thomas Wheeler
General relativity can be seen as a gauge theory of the Lorentz, Poincaré, Weyl, de Sitter, or conformal groups. In most of these, there is little or no difference from the standard formulation in Riemannian geometry, but the higher symmetries — de Sitter and conformal — introduce new features and explain old ones. The potential presence of a cosmological constant, the spacetime metric, cosmological dust, symplectic structure, Kähler structure and even the existence of a timelike direction can all be seen to arise from the underlying group structure.
Weyl Gravity As General Relativity, James Thomas Wheeler
Weyl Gravity As General Relativity, James Thomas Wheeler
James Thomas Wheeler
When the full connection of Weyl conformal gravity is varied instead of just the metric, the resulting vacuum field equations reduce to the vacuum Einstein equation, up to the choice of local units, if and only if the torsion vanishes. This result differs strongly from the usual fourth-order formulation of Weyl gravity.