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arXiv · 1106.1662

Photon propagation in a cold axion background with and without magnetic field

Domenec Espriu·Albert Renau
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Abstract

A cold relic axion condensate resulting from vacuum misalignment in the early universe oscillates with a frequency m, where m is the axion mass. We determine the properties of photons propagating in a simplified version of such a background where the sinusoidal variation is replaced by a square wave profile. We prove that previous results that indicated that charged particles moving fast in such a background radiate, originally derived assuming that all momenta involved were much larger than m, hold for long wavelengths too. We also analyze in detail how the introduction of a magnetic field changes the properties of photon propagation in such a medium. We briefly comment on possible astrophysical implications of these results.

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Domenec Espriu, Albert Renau. 2011-11-28. Photon propagation in a cold axion background with and without magnetic field. https://doi.org/10.1103/physrevd.85.025010

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