2026-04-07 - 2026-04-10
Hier geht es zur AnmeldungDavid James Weir
University of Helsinki
The LIGO and Virgo detectors now regularly detect gravitational waves from compact binary mergers. There is also evidence for a stochastic background of gravitational waves in the data from pulsar timing array networks such as NANOGrav – most likely from supermassive black hole mergers. We are therefore at a turning point in the study of gravitational waves, with observations expanding to multiple frequency bands and source types. Furthermore, many processes in the very early universe would give rise to gravitational wave backgrounds. These could in principle be detected (or constrained) by existing experiments, as well as future missions such as the space-based LISA detector. Furthermore, gravitational waves are the only direct probe we have of primordial nonequilibrium physics prior to recombination.
In these lectures we will explore the physics of first order phase transitions in the early universe and how such phase transitions could source a stochastic cosmological background of gravitational waves. In particular, we will see how simulations both of the gravitational wave production mechanisms as well as the underlying particle physics processes have informed our current understanding. The lectures will be self-contained and provide an introduction both to primordial gravitational wave sources and to the simulation methods used.
