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...
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...
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...
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...
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...
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,...
Certain aspects of phase transition dynamics, at least the initial nucleations and subsequent growth, can be described within the framework of fluctuating hydrodynamics, extended by a scalar order parameter. A strength of this formulation is that the contributions of small and large momenta can be factorized. We describe the ideas and limitations behind this approach, and how it can be used...
In this work, the dynamics of the nucleating scalar field is investigated during
the first-order phase transitions by incorporating one-loop corrections of classical fluctuations.
We contrast our results with traditional methods based on the derivative expansion; show that the latent heat can differ from the effective-potential result; and discuss general hydrodynamic corrections....
In this talk, I will take advantage of recent progress on wall speed determination to provide simple estimates that constrain the wall velocity between two opposite limits: local thermal equilibrium and ballistic. The description of the wall velocity in these limits is significantly simplified compared to conventional methods, which allows for the derivation of analytic formulas valid for slow...
Examples of GW from FOPT in BSM models and WallGo: I present three examples of BSM producing GW: one from SO(10) from the breaking chain $SU(3)_C\times SU(2)_L\times SU(2)_R\times U(1)_{B-L}$ (2506.07182), another from a first-order phase transition of the inflaton coupled to a dark sector (2412.17278) and the third one from reheating through particle production. As we know, uncertainties in...
Terminal velocity of bubble walls in cosmological first-order phase transitions is a key parameter affecting both the primordial gravitational wave signal and baryon asymmetry production in electroweak baryogenesis. In this talk, I present recent results showing that, under local thermal equilibrium, pure hydrodynamic backreaction can lead to steady-state expansion, as confirmed by numerical...
The dynamics of of the electroweak phase transition has profound implications for cosmology and particle physics, and is governed by the density perturbations generated by the expanding bubble. A precise determination of this dynamics, and in particular of the bubble wall velocity, is crucial to assess the experimental signatures of the transition. In this talk, I will report on recent...
We are currently witnessing the dawn of a new era in astrophysics and cosmology, started by the LIGO/Virgo observations of Gravitational Waves (GWs). Recently, also the detection of a stochastic background of GWs at very low frequencies was announced by the Pulsar Timing Array collaborations. In this talk, I will discuss terminal velocities reached by expanding bubble walls and the GW signals...
Predicting the gravitational wave spectrum from symmetry breaking in the early universe during first-order phase transitions is key to understanding these symmetries. In this talk I present our recent advancements in developing a self-consistent framework for predicting such gravitational wave spectra. Our approach enhances existing calculations by providing a more comprehensive treatment of...
We study the irrotational velocity spectra induced in a fluid during a first-order phase transition in the radiation-dominated era. Interactions of the scalar broken-phase bubbles with the fluid generate irrotational velocity and enthalpy profiles which are, together with the statistical time distribution of bubble nucleation and collision, predictive of the gravitational wave spectrum...
Using semi-analytical models, we investigate the power spectrum of gravitational waves generated by sound waves in the plasma during a first-order phase transition in new unexplored scenarios. (i) The phase transition is accompanied by a change of the equation of state from that of pure radiation. This causes the peak of the spectrum to shift to smaller frequencies as the equation of state...
For a wide range of scenarios, the generation of gravitational waves (GWs) from cosmological first-order phase transitions is believed to be dominated by sound waves. Understanding their decay through acoustic turbulence is an important factor in determining the overall intensity of the GW signal. We have simulated acoustic turbulence numerically in three dimensions to study its decay...
The gravitational wave spectrum from sound wave contributions is typically modeled as a double-broken power law with fixed spectral slopes. However, the intermediate slope depends on phase transition parameters, which can help resolve degeneracies when reconstructing these parameters. To improve gravitational wave predictions, we provide an analytic form of this parameter dependence, derived...
In this talk, I will investigate the formation of Primordial Black Holes as the result of the collapse of energy density fluctuations originating from supercooled first-order phase transitions. I will present the results of a simplified approach, where the energy density fluctuations are evolved within the limit of flat FRW Universe. I will show how energy density fluctuations modify the...
In the early Universe, during a phase transition, the surrounding plasma is subjected to a fluid motion sourcing gravitational waves. This fluid motion can be composed of compressional and vortical motions. Most of the time, they are considered distinct and studied independently. However, by analyzing the UETC of the anisotropic stresses, a mixed term combining vortical and compressional...
This talk is consists of two parts. In the first part I will talk about curvature perturbation produced in very strong first-order phase transitions. I will first explain super-hubble curvature perturbation based on 2311.16222, and then move on to hubble-scale curvature perturbation based on 2503.01962. In the second part I change the topic and talk about a new type of formulation of quantum...
I review calculations of gravitational waves from the fluid flows generated by first order phase transition in the early universe, summarise the current status in simulations and modelling, and suggest areas where further progress can be made in preparation for the LISA mission.
