28 July 2025 to 15 August 2025
Albano Building 3
Europe/Stockholm timezone

Gravitational Effects on Sound Waves: A Perturbative Approach for Large Bubbles in Cosmological First-Order Phase Transitions

8 Aug 2025, 11:30
30m
Albano Building 3

Albano Building 3

Hannes Alfvéns väg 12, 10691 Stockholm, Sweden

Speaker

Jun'ya Kume (University of Padova, INFN Padova)

Description

If a cosmological first-order phase transition takes place over the cosmological time scale, gravity must affect the profile of sound waves. To investigate such a regime beyond the self-similarity, we combine a hydrodynamic scheme in the presence of gravity with a fluid computation scheme under energy injection from the bubble wall.
In this talk, I present the results of our (1+1)d hydrodynamic simulations around an expanding bubble in the cosmological background. We find that gravitational effects lead to a thinner fluid shell and reduce the kinetic energy budget, in qualitative agreement with previous discussions on late-time fluid behavior in an expanding universe. Moreover, our simulations reveal the development of sub-structures in the fluid profile for accelerating bubble walls. We also discuss the potential impact of these effects on the broadening of the SGWB spectral plateau.

Primary author

Jun'ya Kume (University of Padova, INFN Padova)

Presentation materials

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