Event

Decoupled hidden sectors in the early universe can easily and generically result in departures from radiation domination prior to BBN, leaving a potentially observable footprint in the distribution of dark matter on very small scales. I'll talk about the gravitational consequences of an era of modified cosmic expansion, maps to the particle physics of decoupled hidden sectors that can realize such eras, and the features in the (linear) matter power spectrum, with an eye toward observability.