Speaker: Samuel Young (Sussex)

Abstract:

Primordial black holes (PBHs) may have formed very early in the universe from the collapse of large density fluctuations, and represent a unique probe which can be used to study the small scales of the early universe. Inflation is believed to have lasted at least 50-60 e-folds, but LSS and CMB can only be used to study roughly the largest 8-10 e-folds inside the Hubble horizon today. By contrast, the constraints from PBHs span around 50 e-folds, although are much weaker. Traditionally, a gaussian distribution has been assumed to derive the constraints, but non-gaussianity can strongly affect the calculation. I will discuss how constraints on the early universe from PBHs change when non-gaussianity and modal coupling is taken into account, as well as taking a specific look at the curvaton model. It will be shown that even relatively small values for the non-gaussianity parameters can affect the constraints by orders of magnitude.