Speaker
Mr
Andrea Palessandro
(CP3-Origins)
Description
Particles in a yet unexplored dark sector with sufficiently large mass and
small gauge coupling may form purely gravitational atoms (quantum gravitational
bound states) with a rich phenomenology. Near-Planckian atoms decay to gravitons immediately after being produced in the very early universe, creating a nearly monochromatic, isotropic and highly energetic gravitational wave signal. If Einstein gravity is valid all the way up to the Planck scale, and the gravitational waves are redshifted from the earliest moments after inflation until today using the standard ΛCDM scenario, the minimum frequency attainable in this scenario is $10^{13}$ Hz, three orders of magnitude above the expected cutoff from primordial gravitational waves. Modified Einstein gravity or non-standard cosmological evolution is needed to bring the frequency below that threshold. Gravitational atoms naturally arise in the minimal PIDM scenario consisting of a GUT-scale scalar particle with only gravitational interactions.
Primary authors
Mr
Andrea Palessandro
(CP3-Origins)
Prof.
Martin S. Sloth
(CP3-Origins)
Dr
Niklas G. Nielsen
(CP3-Origins)
