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GR: Gravitation und Relativitätstheorie

GR I: HV I

GR I.1: Hauptvortrag

Montag, 18. März 2002, 10:30–11:15, HS 20

Also in vacuum, D is different from E: A new look at the foundations of electrodynamics and the lightcone — •Friedrich W. Hehl — Institut für Theoret. Physik, Universität, 50923 Köln

The 1st axiom of electrodynamics, electric charge conservation, yields the inhomogeneous Maxwell equations in terms of the excitations D and H. The Lorentz force (2nd axiom) and magnetic flux conservation (3rd axiom) imply the homogeneous set in terms of the field strengths E and B. These equations are all metric-free and diffeomorphism invariant. A linear ansatz (in vacuum) between excitation and field strength, together with electric-magnetic reciprocity (5th axiom),allow to derive the light cones at each point of spacetime. We discuss the abelian axion, possible birefringence of the vacuum, and the coupling of electromagnetism to the gravitational field. See Rubilar, Obukhov, Hehl e-Print Archive gr-qc/0109012 and Hehl, Obukhov, Fondations of Classical Electrodynamics. Birkhaeuser, Boston (2002).