Detecting Chameleons: The Astronomical Polarization Produced by Chameleon-like Scalar Fields
Abstract
We show that a coupling between chameleon-like scalar fields and photons induces linear and circular polarization in the light from astrophysical sources. In this context chameleon-like scalar fields includes those of the Olive-Pospelov (OP) model describing a varying fine structure constant. We determine the form of this polarization numerically and give analytic expressions in two useful limits. By comparing the predicted signal with current observations we are able to improve the constraints on the chameleon-photon coupling and the coupling in the OP model by over two orders of magnitude. It is argued that, if observed, the distinctive form of the chameleon induced circular polarization would represent a smoking gun for the presence of a chameleon. We also report a tentative statistical detection of a chameleon-like scalar field from observations of starlight polarization in our galaxy.
Keywords
Cite
@article{arxiv.0809.1763,
title = {Detecting Chameleons: The Astronomical Polarization Produced by Chameleon-like Scalar Fields},
author = {Clare Burrage and Anne-Christine Davis and Douglas J. Shaw},
journal= {arXiv preprint arXiv:0809.1763},
year = {2009}
}
Comments
34 pages, 10 figures; updated to reflect published version