2017/08/21 by Masahiro Kawasaki, Fuminobu Takahashi, Masaki Yamada · 2 citations
Physics and Astronomy · #hep-ph #astro-ph.CO #hep-th
paper · pdf · doi:10.1007/jhep01(2018)053
30 pages, 3 figures
arxiv created 2017/08/21 · arxiv updated 2018/02/14
The string theory predicts many light fields called moduli and axions, which cause a cosmological problem due to the overproduction of their coherent oscillation after inflation. One of the prominent solutions is an adiabatic suppression mechanism, which, however, is non-trivial to achieve in the case of axions because it necessitates a large effective mass term which decreases as a function of time. The purpose of this paper is twofold. First, we provide an analytic method to calculate the cosmological abundance of coherent oscillation in a general situation under the adiabatic suppression mechanism. Secondly, we apply our method to some concrete examples, including the one where a string axion acquires a large effective mass due to the Witten effect in the presence of hidden monopoles.