Speaker
Description
A leading candidate for a stochastic source of primordial gravitational waves would be a first order phase transition. Strong electroweak-scale phase transitions in particular stand a good chance of being constrained by gravitational wave data from future missions such as LISA and Taiji, and thus it is important to understand the signal from strong transitions. However, strong transitions also lead to highly nonlinear behaviour over many length- and timescales, which makes for a challenging topic of study both for analytical and simulation approaches. In arXiv:2505.17824 we presented results of large-scale simulations for a strong detonation and deflagration, demonstrating features including the saturation of the signal. Here we extend this work to a scan across wall velocities, bubble separations and phase transition strengths. Employing the field-fluid simulation model (and our SCOTTS code) we study gravitational waves from strong hybrids, explore the role of droplets, and investigate the 'low-frequency' shallow slope. We believe that studies like this will be crucial to solving the 'inverse problem' of constraining (or detecting) a phase transition, given gravitational wave data.