Phase transitions are a ubiquitous part of our everyday life. The boiling of water to make tea or the condensation of vapor on a cool window are familiar examples. Phase transitions also played an important role in the extreme environment of the primordial plasma, during the first fractions of a second after the big bang. It was during this time that the cosmological excess of matter over antimatter was established and the cosmological abundance of dark matter was determined. If we seek to uncover the origin of these cosmic relics, then we should understand how they could have arisen during phase transitions in the early universe. In this talk I will discuss several recent proposals including lepto-bubbles, filtered dark matter, and dark quark nuggets, in which the baryon asymmetry and dark matter are the result of first-order cosmological phase transitions. I will discuss the laboratory and astrophysical signatures including dark matter direct detection, gravitational wave interferometry, and MACHO searches.
Tuesday, November 10, 2020