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Preprint A/04

An astronomical search for evidence of new physics: Limits on gravity-induced birefringence from the magnetic white dwarf RE J0317-853

Oliver Preuss (1), Mark P. Haugan (2), Sami K. Solanki (1), Stefan Jordan (3,4)

(1) Max-Planck-Institut fuer Aeronomie, Katlenburg-Lindau, Germany
(2) Department of Physics, Purdue University, Indiana, USA
(3) Universität Tübingen, Institut für Astronomie und Astrophysik, Germany
(4) Astronomisches Rechen-Institut, Heidelberg, Germany

To be published in: Phys.Rev.D

Abstract. The coupling of the electromagnetic field directly with gravitational gauge fields leads to new physical effects that can be tested using astronomical data. Here we consider a particular case for closer scrutiny, a specific nonminimal coupling of torsion to electromagnetism, which enters into a metric-affine geometry of space-time. We show that under the assumption of this nonminimal coupling, spacetime is birefringent in the presence of such a gravitational field. This leads to the depolarization of light emitted from extended astrophysical sources. We use polarimetric data of the magnetic white dwarf RE J0317-853 to set strong constraints on the essential coupling constant for this effect, giving k² <~ (19 m)².

http://arxiv.org/abs/gr-qc/0405068

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| Impressum Last modified 14 Jun 2004