Warmth and Randomness in Dark Matter Fields

by Prof. Mustafa A. Amin (Rice U.)

Wednesday 8 Oct 2025, 15:00 → 17:00 Europe/Rome

1/1-2 - Aula "C. Voci" (Dipartimento di Fisica e Astronomia - Edificio Marzolo)

I will argue that if dark matter is produced via processes with finite correlation length in the early universe, then there is a lower bound on the mass of dark matter particles [m > 10^(-19) eV]. For such dark matter, there is both (i) a free streaming suppression and (ii) white-noise enhancement in the dark matter density power spectrum. The absence of these in the existing observational data (for example, Ly-a) provides a bound on the mass.  Beyond the bound, I will present a calculation framework for understanding the growth of structure where warmth and/or white noise are relevant. I will discuss nonlinear phenomenon (eg. solitons), resulting from the large initially isocurvature perturbations on small scales.