Gravitational wave forest from string axiverse

by Yuko Urakawa (Nagoya U, Japan)

Friday 18 Jan 2019, 12:00 → 13:00 Europe/Madrid

IFAE Seminar room (IFAE)

Axions predicted in string theory may have a scalar potential which has a
shallower potential region than the conventional cosine potential. I first show
that axions which were located at such shallow potential regions generically
undergo prominent resonance instabilities. We also study non-linear dynamics
of axions caused by these resonance instabilities based on lattice simulation.
We show that string axions in various mass ranges generate gravitational waves
 (GWs) with peaks at various frequencies determined by the mass scales, dubbed
the GW forest. This may allow us to explore string axiverse through future multi-
frequency GW observations. When time permits, I will also discuss our on-going
work about a generation of circularly polarized GWs through gauge fields which
are amplified by the resonance instability of axions.

YukoURAKAWA.pdf