Status | Confirmed |
Seminar Series | SEM-GRECO |
Subjects | astro-ph |
Date | Monday 3 May 2021 |
Time | 11:00 |
Institute | IAP |
Seminar Room | Webinar for zoom details contact fumagall@iap.fr |
Speaker's Last Name | Gorghetto |
Speaker's First Name | Marco |
Speaker's Email Address | |
Speaker's Institution | Weizmann Institute |
Title | Gravitational Waves from Axions |
Abstract | Axions are among the best motivated candidates for new physics. If the Peccei-Quinn symmetry associated with an axion has been ever restored after inflation, axion strings form and inevitably produce a contribution to the stochastic gravitational wave background. In this talk I will discuss the resulting gravitational wave spectrum by combining effective field theory analysis with numerical simulations. I will show that a single ultralight axion-like particle with a decay constant larger than 10^{14} GeV and any mass between 10^{-18} and 10^{-28} eV leads to an observable gravitational wave spectrum, and still compatible with constraints from dark matter overproduction, isocurvature and dark radiation. Since the spectrum extends over a wide range of frequencies, the resulting signal could be detected by multiple experiments. I will also comment on the recent possible NANOgrav signal in light of these results. |
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