BEGIN:VCALENDAR VERSION:2.0 PRODID:-//linuxsoftware.nz//NONSGML Joyous v1.4//EN BEGIN:VEVENT SUMMARY:How Fast Does the Bubble Grow? Hydrodynamical Obstruction in Numer ical Simulations DTSTART:20230706T143000Z DTEND:20230706T160000Z DTSTAMP:20260627T141140Z UID:ceefee7c-57fc-499f-a191-57efb4a8bf45 SEQUENCE:1 CREATED:20230703T091546Z DESCRIPTION: ABSTRACT: Terminal velocity reached by bubble walls in first order phase transitions is an important parameter determining both primord ial gravitational-wave spectrum and production of baryon asymmetry in mode ls of electroweak baryogenesis. We developed a numerical code to study the real-time evolution of expanding bubbles and investigate how their walls reach stationary states. Our results agree with profiles obtained within t he so-called bag model with very good accuracy\, however\, not all such so lutions are stable and realised in dynamical systems. Depending on the exa ct shape of the potential there is always a range of wall velocities where no steady state solutions exist. This behaviour in deflagrations was expl ained by hydrodynamical obstruction where solutions that would heat the pl asma outside the wall above the critical temperature and cause local symme try restoration are forbidden. For even more affected hybrid solutions cau ses are less straight forward\, however\, we provide a simple numerical fi t allowing one to verify if a solution with a given velocity is allowed si mply by computing the ratio of the nucleation temperature to the critical one for the potential in question. LAST-MODIFIED:20230703T091546Z LOCATION:Sala de Seminários do DF\, Pavilhão de Física\, 2º piso URL:http://df.vps.tecnico.ulisboa.pt/pt/eventos/how-fast-does-the-bubble-g row-hydrodynamical-obstruction-in-numerical-simulations/ X-ALT-DESC;FMTTYPE=text/html:

ABSTRACT: < /p>

Terminal velocity reached by bubble walls in first order phase transitions is an important parameter determining both p rimordial gravitational-wave spectrum and production of baryon asymmetry i n models of electroweak baryogenesis. We developed a numerical code to stu dy the real-time evolution of expanding bubbles and investigate how their walls reach stationary states.

Our results agree with profiles o btained within the so-called bag model with very good accuracy\, however\, not all such solutions are stable and realised in dynamical systems. Depe nding on the exact shape of the potential there is always a range of wall velocities where no steady state solutions exist. This behaviour in deflag rations was explained by hydrodynamical obstruction where solutions that w ould heat the plasma outside the wall above the critical temperature and c ause local symmetry restoration are forbidden.

For even more aff ected hybrid solutions causes are less straight forward\, however\, we pro vide a simple numerical fit allowing one to verify if a solution with a gi ven velocity is allowed simply by computing the ratio of the nucleation te mperature to the critical one for the potential in question.

END:VEVENT END:VCALENDAR