As the detection of a stochastic gravitational wave (GW) background from the early universe becomes increasingly promising, signals from hypothetical first-order phase transitions are attracting growing interest. Predicting these signals often requires the solution of plasma dynamics at macroscopic scales, which, in turn, depends on the phenomena that characterize the phase transition at microscopic scales. Therefore, various assumptions on distinctive scales and their separation are usually employed to enable concrete evaluations. This workshop aims to bring together researchers from both the microscopic and macroscopic communities to collaboratively address theoretical shortcomings and refine current GW spectral templates across different regimes:
1) Microscopic scales – Quantitative uncertainties related to the fundamental phase transition parameters within minimal BSM scenarios, where a scalar field drives the symmetry-breaking mechanism.
2) Intermediate scales – Different approaches for describing the interactions between the scalar field and the plasma, including bubble wall dynamics and plasma viscosity. A key question is whether the bubble wall runs away or reaches a terminal velocity.
3) Macroscopic scales – Reliability of the approximations employed to connect to large-scale phenomena during and after the phase transition, such as collisions between the bubbles, the development of turbulence, and the evolution of sound shells.
confirmed speakers:
1) Microscopic scales:Andrii Dashko (DESY)Oliver Gould (U. Nottingham)Anna Kormu (U. Helsinki)Kari Rummukainen (U. Helsinki)Bogumila Swiezewska (U. Warsaw)
2) Intermediate scales:Ryusuke Jinno (U. Kobe)Benoit Laurent (U. McGill)Wen Yuan Ai (U. Vienna)
3) Macroscopic scales:Jani Dahl (U. Helsinki)Lorenzo Giombi (U. Helsinki)
Marek Lewicki (U. Warsaw)Mark Hindmarsh (U. Helsinki)Tina Kahniashvili (U. Canergie Mellon)Thomas Konstandin (DESY)Antonino S. Midiri (U. Geneva)
Format: online participation is possible, in-person attendance is limited to 35 participants. Talks are in person.