Advancing gravitational wave predictions from cosmological first-order phase transitions

Session

Microscopic scales

25 Aug 2025, 10:30

4/3-006 - TH Conference Room (CERN)

Conveners

Microscopic scales: Morning session

• Philipp Schicho (University of Geneva)

Microscopic scales: Afternoon session

• Hyun Min Lee

Microscopic scales: Short talks

• Philipp Schicho (University of Geneva)

Microscopic scales: Morning session

• Alberto Roper Pol

Microscopic scales

• Jorinde van de Vis (CERN)

Microscopic scales: Panel discussion

• Philipp Schicho (University of Geneva)

Description

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Presentation materials

discussion_microscopic_scales_results.pdf

19. Precise predictions for cosmological phase transitions

Bogumila Swiezewska (University of Warsaw)

25/08/2025, 10:30

In this talk, I will discuss how to formulate precise predictions for the parameters of supercooled cosmological first-order phase transitions. I will explain the construction of the high-temperature effective field theory (EFT) applicable to the issue of nucleation. Using this EFT, I will show how to consistently formulate predictions at next-to-leading order in perturbation theory, paying...

20. An update on non-perturbative calculations for strong phase transitions

Anna Kormu

25/08/2025, 11:15

Nucleation rate computations are of broad importance in particle physics and cosmology. Previously, these nucleation rates have generally been calculated perturbatively, but those calculations depend on the semiclassical picture of the bubble and its fluctuations, and different orders of perturbative calculation yield very different results. In this talk, I will give you an update on...

16. Thermal nucleation in perturbation theory

Joonas Hirvonen (University of Nottingham)

25/08/2025, 13:30

Microscopic scales

Cosmological first-order phase transitions may have generated an observable gravitational wave background, providing a unique window into physics beyond the Standard Model. A crucial step in predicting this background is the reliable computation of bubble nucleation rates. In this talk, I will discuss how techniques, such as effective field theories, Boltzmann equations and real-time...

37. Cosmological phase transitions without high-temperature expansions

Pablo Navarrete (University of Helsinki)

25/08/2025, 14:15

Accurate determination of equilibrium thermal parameters in strong first-order phase transitions — in particular, the critical
temperature and latent heat — is essential for predicting gravitational-wave signals detectable by upcoming spaceborne observatories.

In perturbation theory, the evaluation of the thermal effective potential for such strong transitions is hampered by the presence...

4. Higher-order-operator corrections to phase transitions parameters in dimensional reduction

Luis Gil (Universidad de Granada)

25/08/2025, 15:30

The construction of 3D EFTs for phase transition (PT) computations has been taken to unprecedented levels of precision in the recent years, considering effects up to 3-loop order. However, the contributions from higher-dimensional effective operators (EO) that arise at the same order in the power counting have been generally neglected in the literature.

In this talk, we will analyze the...

11. Finite-temperature bubble-nucleation with shifting scale hierarchies

Maciek Kierkla

25/08/2025, 15:35

Focusing on supercooled PTs in models with classical scale symmetry, we investigate the limitations of derivative expansions in constructing a thermal EFT description for bubble nucleation. We show that derivative expansion for gauge field fluctuations diverges because the gauge field mass varies strongly between the high- and low-temperature phases. By computing the gauge fluctuation...

35. RG-improved Partial Dressing Thermal REsummation for accurate Veff calculations within and beyond the high-T approximation

David Richard Curtin (University of Toronto)

25/08/2025, 15:40

We consistently RG-improve the 4D perturbative imaginary time formalism calculation of the scalar effective potential at finite temperature using the partial dressing thermal resummation scheme. This avoids overcounting, is easy to implement numerically using only one-loop results, gives results with high precision comparable to dimensional reduction calculations in the high-T regime, but is...

31. Bubble nucleation vs phase mixing around the spinodal temperature

Taehyun Jung (Institute for Basic Science)

26/08/2025, 09:15

Phase transitions, in general, involve a nonzero spinodal temperature at which the potential barrier disappears. In some models of cosmological first-order phase transitions, supercooling is maintained until around the spinodal temperature, so the phase transition proceeds during the time when the potential barrier disappears rapidly. In this talk, I will discuss whether, in this circumstance,...

7. Limits of EFTs at finite temperature for strong phase transitions

Fabio Bernardo

26/08/2025, 15:40

Phase transitions are violent and interesting phenomena that could have occurred in the early universe. Possible techniques to study these phenomena can be used in the presence of a hierarchy of scales, leading to the construction of finite temperature Effective Field Theories by integrating out heavier scales. These EFTs are reliable when the dynamics are mainly encoded in the most relevant...