Cosmological correlators encode rich information about quantum field theories in a cosmological background and are key observables of cosmological collider physics. However, their analytical computation is a hard problem due to the inherent complexities of these functions. Recently, we solved this problem for all tree-level massive correlators and revealed a universal structure of family...
Parity-violating interactions are ubiquitous phenomena in particle physics. If they are significant during cosmic inflation, they can leave imprints on primordial perturbations and be observed in correlation functions of galaxy surveys. Importantly, parity-violating signals in the four-point correlation functions (4PCFs) cannot be generated by Einstein gravity in the late universe on large...
We explore a generic class of composite dark matter candidates arising from confining dark sectors, where phase transitions—especially deconfinement-confinement and chiral symmetry breaking—can generate stochastic gravitational waves. Using a combination of lattice results and effective field theory approaches such as the Polyakov Loop and PNJL models, we analyze the dynamics of these phase...
GUT phase transition is generally considered as an unobservable process due to its ultra-high energy scale, and the monopole problem associated with GUT phase transition is one motivation of inflation. We propose that if a first-order GUT phase transition happens during inflation, the induced gravitational waves (GWs) are redshifted and deformed, and might be observed today in GW...
Connecting inflation with neutrino physics through non-thermal leptogenesis via direct inflaton-right-handed neutrino (RHN) coupling naturally incorporates neutrino reheating, leaving no ambiguity regarding the early history of the Universe. We demonstrate that non-thermal leptogenesis from inflaton decay expands the viable parameter space compared to thermal leptogenesis and provides a...
The minimal left-right symmetric model (mLRSM) provides an elegant and testable
framework for addressing the origin of neutrino masses. We examine the constraints on the sub-GeV sterile neutrino in the type-II seesaw scenario of the mLRSM without left-right mixing, taking limits from collider searches, meson decays, supernovae, neutrinoless double beta ($0\nu\beta\beta$) decay and cosmology....
We explore new sources of gravitational waves from the early universe in well motivated new physics models.
In this talk, I will present a novel mechanism that may provide either the B-L violating source term or a brand-new spectator process for Leptogenesis mechanism. Given initial densities for various SM fermions that keep B-L=0, non-zero baryon asymmetry of the universe can be generated.
Cosmological stasis is a phenomenon in which multiple energy components with different equation-of-state parameters maintain constant abundances for an extended period despite the expansion of the universe. In this talk, I review the how stasis arises and discuss the possible implications of this phenomenon in observations. These include characteristic imprints in the stochastic...
The computation of bounce action in a phase transition involves solving partial differential equations, inherently introducing non-negligible uncertainty. Deriving characteristic temperatures and properties of this transition necessitates both differentiation and integration of the action, thereby exacerbating the uncertainty. We fit the action curve as a function of temperature to mitigate...
The possibility of first-order phase transition in the early Universe is drawing attention in view of gravitational wave observations planned for the 2030's. In this talk I will first report updates on Higgsless simulations for gravitational wave production, and then report (negative) results regarding primordial black hole formation from strong phase transitions. Then I will discuss possible...
Cosmological phase transitions, particularly the electroweak one, continue to draw attention due to their potential to generate a stochastic gravitational wave background and to provide a possible mechanism for baryogenesis.
In this talk, I will discuss the perturbative description of such transitions, focusing on recent developments in high-temperature effective field theory (EFT) relevant...
The study of Higgs boson pair production at the LHC and potential future high-energy colliders offers a unique opportunity to probe the dynamics of electroweak symmetry breaking. In the Standard Model, non-resonant di-Higgs production enables direct access to the Higgs trilinear self-coupling, serving as a crucial test of the Higgs mechanism. Beyond the Standard Model, both resonant and...
The PBH can be formed during a delayed EWPT. Using xSM as a benchmark, we identify the features of the parameter space that tend to generate large fraction of PBH, which can be explored by collider searches and GW experiments aiming at the GW signal from EWPT. On the other hand, the PBH can form binaries either with another PBH or with astrophysical BH. GW will also be emitted from the...
We present a general algorithm—the Young Tensor Method—for systematically constructing complete and independent operator bases in effective field theories. This method is applied to a variety of theories, including the Standard Model Effective Field Theory (SMEFT) and low-energy effective field theories. In the process, we introduce the concept of the J-basis, a generalized partial wave basis...
The detection of gravitational waves has created a pressing need for high-precision theoretical models for binary systems. In this talk, I will review recent progress in the analytic computation of physical observables for binary black hole and neutron star systems using modern on-shell methods. This research program represents a concerted effort between the fields of quantum field theory and...
U(1) dark and darker sectors accommodating viable dark matter candidate(s) will be discussed. When the additional U(1) symmetry undergoes spontaneous breaking, the dark sector often exhibits a characteristic phase transition pattern capable of producing detectable gravitational wave signals. A gauge-invariant formulation of the scalar potential associated with this phase transition will be...
We establish a first principles, systematic framework for determining the bubble wall velocity during a first order cosmological phase transition. This framework, based on non-local Kadanoff-Baym equations, incorporates both macroscopic fluid dynamics and microscopic interactions between the bubble wall and particles in the plasma. Previous studies have generally focused on one of these two...
We consider the generic picture of DM freeze-in when the dark sector is strongly coupled and confined at low energy scales. Two scenarios, namely the UV and IR freeze-in production and accompanying unique phenomena.
We investigate whether collider experiments can reach the quantum limit of precision, defined by the quantum Fisher information (QFI), using only classical observables such as particle momenta. As a case study, we focus on the τ+τ− system and the decay channel τ → πν, which offers maxi- mal spin-analyzing power and renders the decay a projective measurement. We develop a general framework to...
The detection of the stochastic gravitational-wave background (SGWB) offers a powerful window into both astrophysical and cosmological phenomena. In this talk, we provide a brief overview of the current status of SGWB measurements and their implications for cosmological first-order phase transitions. We explore search strategies that future space-based interferometers -- using LISA as a...
The muon collider, a proposed facility that combines high collision energies with a clean experimental environment, offers compelling opportunities for advancing particle physics. This talk will explore its dual strengths: enabling precision measurements within the Standard Model and extending the search for new physics. We will specifically highlight its exceptional potential for probing the...
In this talk, I will review recent progress of using LIGO observations to constrain parameter space of axion-like particles. I will also discuss the frontiers of understanding the co-evolution of axion clouds and binary systems, including both stellar-mass black hole binaries and extreme mass-ratio inspirals.
We present a complete Lagrangian describing axion interactions with pseudoscalar and (axial-)vector mesons within the three light-flavor quark framework. This formulation incorporates both the standard chiral Lagrangian and the full Wess-Zumino-Witten (WZW) term. By including instanton effects associated with the anomalous U(1)_A symmetry, we demonstrate that physical observables remain...
This talk discusses studies of non-perturbative (NP) effects using Energy Correlators at colliders. I will explore the adaptation of energy correlators to heavy quarkonium studies, highlighting their potential for elucidating hadronization processes.
We know from the discovery of the Higgs boson that electroweak symmetry is broken through the Higgs mechanism, but we expect this should be restored at high temperatures in the early universe. Thus we believe the matter in the universe underwent a dramatic change of state as the universe cooled down. Electroweak phase transitions have many important consequences, for example if strongly...
Cosmological first-order phase transitions are typically associated with physics beyond the Standard Model, and thus of great theoretical and observational interest. In this talk, I will show that a broad class of non-thermal first-order phase transitions could generate distinct large-scale isocurvature in dark radiation that can be observable in the CMB. We derive constraints on $\Delta...
In this talk, I will review the new physics mechanisms based on first-order phase transitions in recent years.
A strong first-order electroweak phase transition (SFOEWPT) is a critical prerequisite for realizing electroweak baryogenesis in the early universe. However, lattice simulations indicate that the contribution from the Standard Model (SM) Higgs alone is insufficient to produce a strong first-order phase transition. New physics, particularly beyond-the-SM (BSM) scenarios with scalar masses...
In this talk, I will review our recent progress on the numerical simulation of vacuum decay at finite temperature.
There is a growing interesting in studying dark sectors, which are only feebly coupled to the Standard Model sector, but could be strongly self-coupled. The potential existence of bound state in dark sectors, motivated by hints of strongly self-interacting dark matter, results in novel phenomenology. This talk discusses its applications in dark matter physics and beyond, as well as the methods...
First-order phase transitions in the early universe can produce a stochastic background of gravitational waves (GWs), where sound waves in the plasma are expected to be the dominant source in the absence of extreme supercooling. A precise prediction of the GW spectrum therefore requires a careful treatment of the plasma dynamics. In this work we investigate three key effects: inverse...
The amount of information propagated by an intermediate heavy particle exhibits characteristic features in inelastic scatterings with n$\geq$3 final particles. As the total energy increases, the entanglement entropy, between its decay products and other final particles, exhibits a universal sharp dip, suppressed by its small decay rate. This indicates an entanglement suppression from a...
We present a numerical investigation of primordial black hole (PBH) formation from super-horizon curvature perturbations and the subsequent generation and propagation of sound waves, which can serve as a new source of stochastic gravitational wave backgrounds (SGWBs) presented in a companion letter. Using the Misner-Sharp formalism with an excision technique, our simulations extend to...
Topological field solutions – such as sphaleron, monopole, and cosmic strings – can have important implications on the unsolved questions of our universe, notably the origin of baryon asymmetry and the nature of dark matter. Many baryogenesis mechanisms (for example, electroweak baryogenesis and leptogenesis) depend on sphaleron transition; consequently, a theoretical rubost and consistent...
