2002/03/26 by Friedrich W. Hehl, Hehl, Friedrich W., Yuri N. Obukhov +3 · 2 citations
Engineering · Physics and Astronomy · #Geophysics and Sensor Technology #Quantum and Classical Electrodynamics #Relativity and Gravitational Theory #gr-qc #hep-th
paper · pdf · doi:10.48550/arxiv.gr-qc/0203096
17 pages, LaTeX2e. Invited paper, Proceedings 1st Mexican Meeting on Math. and Exp. Physics, Mexico City, Sept.2001, corrected and slightly updated
arxiv created 2002/03/26 · arxiv updated 2009/11/30
In the framework of generally covariant (pre-metric) electrodynamics (``charge & flux electrodynamics''), the Maxwell equations can be formulated in terms of the electromagnetic excitation H=(\cal D, \cal H) and the field strength F=(E,B). If the spacetime relation linking H and F is assumed to be \em linear, the electromagnetic properties of (vacuum) spacetime are encoded into 36 components of the vacuum constitutive tensor density χ. We study the propagation of electromagnetic waves and find that the metric of spacetime emerges eventually from the principal part (1)χ of χ (20 independent components). In this article, we concentrate on the remaining skewon part (2)χ (15 components) and the axion part (3)χ (1 component). The skewon part, as we'll show for the first time, can be represented by a 2nd rank traceless tensor \not Sij. By means of the Fresnel equation, we discuss how this tensor disturbs the light cones. Accordingly, this is a mechanism for violating Lorentz invariance and time symmetry. In contrast, the (abelian) axion part (3)χ does \em not interfere with the light cones.