Novel Gravitational Wave Signals from Dark Phase Transitions

by Bibhushan Shakya (DESY)

Wednesday 12 Oct 2022, 11:30 → 12:30 Europe/Zurich

4/2-011 - TH common room (CERN)

First order phase transitions are well-motivated and extensively studied sources of gravitational waves (GWs) from the early Universe. The vacuum energy released during such transitions is assumed to be transferred primarily either to the expanding walls of bubbles of true vacuum, whose collisions source GWs, or to the surrounding plasma, producing sound waves and turbulence, which act as GW sources. In this talk, we will explore an alternative possibility that has so far not been considered: in phase transitions in dark sectors, the released energy can get transferred primarily to noninteracting particles, which do not admit a fluid description but act as individual particles that simply free-stream. As we will discuss, GWs from such configurations have qualitatively distinct characteristics compared to conventional sources, and are potentially observable with near-future GW detectors.