Speaker
Mustafa Amin
Description
I will argue that if the density of dark matter in the early
universe is dominated by subhorizon, non-relativistic field modes,
then there is a relatively model-independent lower bound on the
mass of dark matter particles $m > 10^{-19}\, {\rm eV}$. The bound comes from considerations of (observed lack of) suppression of structure due
to free streaming, and (observed lack of) an enhancement due to a
isocurvature white noise contribution. Additional assumptions
relevant for some well-explored models can strengthen the bound
significantly. Time permitting, I will also discuss some novel
phenomenology of ultralight bosonic dark matter with different
intrinsic spin.
