8 papers
Primordial black hole formation in matter domination
Ehsan Ebrahimian, Ali Akbar Abolhasani, Mehrdad Mirbabayi
We study Primordial Black Holes (PBHs) formed by the collapse of rare primordial fluctuations during an early period of Matter Domination. The collapse threshold strongly depends o…
How Heavy Can Moduli Be?
Mehrdad Mirbabayi, Giovanni Villadoro
In Kaluza-Klein (KK) compactification of gravitational theories, moduli fields, which are scalar fields associated to the deformations of the compact manifold, are typically lighte…
Structure Formation with Warm White Noise: Effects of Finite Number Density and Velocity Dispersion in Particle and Wave Dark Matter
Mustafa A. Amin, M. Sten Delos, Mehrdad Mirbabayi
We investigate the evolution of density perturbations in dark matter, including the new combined effects of finite number density and non-zero velocity dispersion. Using a truncate…
Early Growth of Structure in Warm Wave Dark Matter
Mustafa A. Amin, Simon May, Mehrdad Mirbabayi
We explore the growth of structure in wave-like dark matter models, where the field and density spectra are peaked at sub-horizon wavenumbers. Starting with the Schrödinger-Poisso…
An infrared bound on the ultraviolet bounce
Mehrdad Mirbabayi, Giovanni Villadoro
Sometimes a local minimum is known to be a metastable vacuum inside the low-energy EFT, but the true vacuum lies outside, and the bounce solution mediating the decay cannot be foun…
An Observer's Measure of De Sitter Entropy
Mehrdad Mirbabayi
The two-point correlation function of a massive field , measured along an observer's worldline in de Sitter (dS), decays exponentially as .…