arXiv subjects

Fa Peng Huang

Publications and source records attributed to Fa Peng Huang.

At least 19 recordsLinked to original sources

arXiv2026

Precise bubble wall velocity in a specific phase transition pattern in the CxSM and beyond

The bubble wall velocity is a key quantity in cosmological first-order phase transitions, with important implications for electroweak baryogenesis, gravitational wave signals, the dark matter relic density and primordial black holes formed during the phase transition, and so on. However, it is often treated as a free input in phenomenological studies, while a self-consistent determination remains challenging. In this work, taking the complex singlet extension of the Standard Model as an example, we investigate the bubble wall dynamics and velocity in a specific electroweak phase transition pattern where both the Higgs field and the coupled singlet scalar experience friction. The microscopic friction arising from particle interactions with the plasma is evaluated using Boltzmann transport equations, while the macroscopic plasma response is described through hydrodynamic analysis. By applying the steady state force balance condition, we numerically determine the bubble wall velocity for different model parameters. We show that the wall velocity is governed by the competition between the driving force from the effective potential and plasma friction, and that its variation can significantly affect the baryon asymmetry. Our study provides a quantitative investigation of bubble wall dynamics in this overlooked phase transition pattern and its implications for early Universe phenomenology.

hep-ph↗

arXiv2026

Model Parameter Reconstruction of Electroweak Phase Transition with TianQin and LISA: Insights from the Dimension-Six Model

We investigate the capability of TianQin and LISA to reconstruct the model parameters in the Lagrangian of new physics scenarios that can generate an electroweak SFOPT. Taking the dimension-six Higgs operator extension of the Standard Model as a representative scenario for a broad class of new physics models, we establish the mapping between the model parameter $Λ$ and the observable spectral features of the stochastic gravitational wave background. We begin by generating simulated data incorporating Time Delay Interferometry channel noise, astrophysical foregrounds, and signals from the dimension-six model. The data are then compressed and optimized, followed by geometric parameter inference using both Fisher matrix analysis and Bayesian nested sampling with PolyChord, which efficiently handles high-dimensional, multimodal posterior distributions. Finally, machine-learning techniques are employed to achieve precise reconstruction of the model parameter $Λ$. For benchmark points producing strong signals, parameter reconstruction with both TianQin and LISA yields relative uncertainties of approximately $20$-$30\%$ in the signal amplitude and sub-percent precision in the model parameter $Λ$. The sub-percent precision reflects the statistical reconstruction capability of the detectors in an idealized setting: it incorporates the machine-learning inference uncertainty and is established at a fixed bubble wall velocity, while theoretical uncertainties in the effective potential calculation are not included.

hep-ph↗

arXiv2026

Dark Matter Production from Bubble Collisions during a First-Order Phase Transition at the End of Inflation

We study whether a first-order phase transition at the end of inflation can generate the observed dark matter abundance through bubble collisions. The transition occurs in a spectator scalar sector with an inflaton-dependent effective potential, so that the nucleation rate grows during inflation and becomes significant only near its end. We identify the region of parameter space in which vacuum decay is dominated by the Coleman--De~Luccia channel, the Hawking--Moss transition remains subdominant, and the nucleated bubbles admit a consistent physical interpretation in an inflating background. Requiring also that the phase transition completes successfully, we then analyze particle production from bubble collisions. In the viable regime, elastic self-scatterings of the spectator particles can efficiently redistribute their momenta, while their decay into dark matter provides the dominant channel for transferring the spectator population to the dark sector. Other competing number-changing or sink processes remain inefficient compared with the Hubble expansion. The final relic abundance receives contributions from both direct production in bubble collisions and the subsequent decay of spectator field particles. We find that the observed dark matter abundance can be accommodated, within the order-of-magnitude accuracy of the collision-production treatment, in a restricted region of parameter space.

hep-ph↗

arXiv2026

Freeze-in gravitational waves and dark matter in warm inflation

Recent study [1] has suggested that warm inflation may be realized with a minimal extension of the Standard Model by a single scalar inflaton field with an axion-like coupling to gluons. Motivated by this framework, we investigate the gravitational wave spectrum and graviton-portal dark matter production through the freeze-in process generated during warm inflation scenarios. We perform a comparative analysis for different dissipation terms, focusing on their distinct gravitational wave signatures in the high-frequency regime. Our findings reveal qualitative and quantitative differences in the spectral behavior, offering a preliminary pathway for exploring inflationary and dark matter models through high-frequency gravitational wave signals.

hep-ph↗

arXiv2026

Accretion Disk Perturbations and Their Effects on Kerr Black Hole Superradiance and Gravitational Atom Evolution

Kerr black hole (BH) superradiance can form gravitational atoms and produce characteristic gravitational-wave signals, providing a probe of ultralight bosons and dark matter. In realistic systems, accretion-disk gravity can shift energy levels and mix states, modifying the effective superradiant growth. We model the disk as a weak external perturbation via a multipole expansion and derive an effective three-level Hamiltonian for the $n=2$ subspace $\{\ket{211},\ket{210},\ket{21-1}\}$ in the weak-coupling regime. The leading disk effect is the quadrupolar ($\ell_d=2$) tidal field, whose symmetries fix the selection rules: axisymmetry gives only diagonal shifts, equatorial nonaxisymmetry activates $\Delta m=\pm2$ mixing ($\ket{211}\leftrightarrow\ket{21-1}$), and breaking equatorial reflection opens $\Delta m=\pm1$ couplings involving $\ket{210}$. As illustrations, a transient equatorial $m=2$ spiral wave drives the resulting two-level system and can suppress superradiance by populating a decaying mode, while a quasi-static warp produces full three-level mixing and can generate narrow ``growth gaps'' near accidental near-degeneracies, with the same static reshuffling also allowing enhancement when weight shifts toward the growing mode. These findings demonstrate that accretion disk perturbations are a crucial environmental factor in determining the dynamics of BH superradiance and the evolution of boson clouds, thereby providing a more reliable theoretical basis for assessing the detectability of ultralight bosons in realistic astrophysical settings.

gr-qc↗

arXiv2026

Primordial Black Hole Formation and Multimessenger Signals in a Complex Singlet Extension of the Standard Model

We investigate the formation of primordial black holes (PBHs) induced by a first-order electroweak phase transition in a realistic renormalizable framework, the complex singlet extension of the Standard Model. We perform a quantitative analysis of the PBH abundance and identify parameter regions consistent with current microlensing constraints. Furthermore, we show that the same parameter space predicts observable stochastic gravitational waves within the sensitivities of future space-based detectors, as well as a sizable deviation in the Higgs triple coupling that can be probed at future lepton colliders. Our results highlight a comprehensive multimessenger framework in which PBH, gravitational wave, and collider observations can jointly test the dynamics of a strongly first-order electroweak phase transition in the early Universe.

hep-ph↗

arXiv2026

A New Source of Phase Transition Gravitational Waves: Heavy Particle Braking Across Bubble Walls

Motivated by the new heavy dark matter production mechanism from cosmic phase transition, we propose a novel mechanism for the generation of microscopic gravitational waves (GWs) during cosmological first-order phase transitions arising from the braking of heavy particles as they traverse bubble walls. Unlike the well-known sources such as bubble collisions, sound waves, or turbulence in the plasma, this mechanism originates from the direct interaction between massive particles and the expanding bubble wall. We use quantum field theory to rigorously compute the gravitational radiation. The resulting GW spectrum exhibits distinctive features: The peak frequency is tightly correlated with the bubble wall velocity, while the peak amplitude scales as the fourth power of the heavy particle mass. These unique dependencies offer a new observational handle on particle physics beyond the Standard Model. We illustrate this mechanism within a specific model framework and demonstrate its viability. Our findings enrich the landscape of phase transition GW sources and open new avenues for more directly probing heavy particle dynamics and new physics models in the early universe.

hep-ph↗

arXiv2026

Rapid post-merger gravitational-wave signals from magnetic black hole superradiance: novel approach to detect magnetic monopole and ultralight boson

We present an analytic framework showing that a spinning black hole with net magnetic charge exhibits a greatly enhanced superradiant instability against charged scalar fields compared with the neutral Kerr case. The enhancement arises from the monopole-induced reduction of the centrifugal barrier, $\ell(\ell+1)\to\ell(\ell+1)-q^2$, encoded by an effective quantum number $\ell_q$, with $q=eP=N/2$ fixed by Dirac quantization. This deepens the bound-state potential well and increases the instability growth rate. The resulting cloud can source near-monochromatic continuous gravitational waves (GWs). For a charged complex scalar, the stress tensor of a single monopole-harmonic sector is stationary, so the leading $2\omega$ GW source instead arises from coherent north--south, equivalently charge-conjugate, cross terms. These select $(\tilde{\ell},\tilde{m},\tilde{\omega})=(2q,+2q,+2\omega)$ and its conjugate $(2q,-2q,-2\omega)$. We find $P_{\rm GW}\propto(E_NE_S/M^2)\alpha^{4\ell_q+8}$, or $P_{\rm GW}\propto(E_c/M)^2\alpha^{4\ell_q+8}$ for a balanced cloud, rather than the neutral-Kerr scaling $\alpha^{4\ell+10}$. This motivates prompt post-merger searches for magnetic monopoles and ultralight bosons. Unlike the Kerr case, where the signal turn-on may be delayed by years to centuries, a magnetic remnant can form a cloud and emit a stronger continuous signal within weeks to months. For $M\sim10^6M_\odot$, the signal can appear within weeks in the mHz band with strain $h\sim10^{-20}$.

gr-qc↗

arXiv2025

New dark matter production mechanism and the gravitational wave signals

The microscopic origin and production mechanism of dark matter (DM) remain central questions in cosmology and particle physics. While thermal freeze-out has long dominated DM model building, alternative non-thermal scenarios are gaining prominence. In this work, we explore novel production channels for heavy DM candidates, including pseudo-Nambu-Goldstone bosons (pNGBs), Q-balls, and filtered DM arising from early-universe phenomena such as primordial black hole (PBH) evaporation, superradiance, and first-order phase transitions. We demonstrate that these mechanisms naturally generate gravitational wave signals detectable by future observatories, such as LISA, TianQin, Taiji, and Cosmic Explorer. This multi-messenger approach offers a promising pathway to probe the origin and nature of DM beyond conventional paradigms.

hep-ph↗

arXiv2025

Multimessenger search strategy for composite dark matter with white dwarf data and gravitational wave detectors

The nature of dark matter (DM) remains one of the most challenges in modern physics. Composite or macroscopic DM present a compelling alternative to conventional particle DM, yet their terrestrial search is notoriously challenging due to low number density. This Letter presents a unified, multimessenger search strategy for composite DM, dramatically improving existing constraints and proposing a new detection method. We first perform a model independent update of astrophysical constraints from compact objects, utilizing systematic calculations and additional white dwarf data related to ignition and subsequent supernovae. Crucially, for the first time, we explore novel signals of composite DM in future gravitational wave detectors like LISA, TianQin, and Taiji, performing detailed signal to noise ratio and Fisher matrix analyses. We demonstrate that these detectors will possess the requisite sensitivity to probe untouched regions of the DM parameter space. Our results underscore the unique power of the multimessenger paradigm spanning stellar astrophysics and gravitational wave astronomy to explore this distinct and challenging frontier of DM physics. Our analyses extend broadly to a wide range of macroscopic or composite DM scenarios.

astro-ph.HE↗

arXiv2025

Effects of Early-Universe Inhomogeneity on Bubble Formation: Primordial Black Holes as an Extreme Case

Our early Universe is not perfectly homogeneous and it may contain some inhomogeneous sources, which might distort the local spacetime and modify the bubble nucleation rate. Taking the primordial black hole as an extreme example, we investigate the bubble nucleation rate of a first-order phase transition in the vicinity of primordial black holes or other primordial gravitational sources. Our analysis reveals that the presence of primordial black holes can reduce the effective action and might modify the nucleation rate due to their gravitational effects, potentially altering the dynamics of the phase transition in the early universe and producing new gravitational wave signals since the gravitational effects of the primordial black hole or other possible inhomogeneous sources could lead to nucleation of non-spherical symmetric bubbles.

hep-ph↗

arXiv2025

New Physics Search at the CEPC: a General Perspective

The Circular Electron-Positron Collider (CEPC), a proposed next-generation Higgs factory, provides new opportunities to explore physics beyond the Standard Model (SM). With its clean electron-positron collision environment and the ability to collect large samples of Higgs, W, and Z bosons, the CEPC enables precision measurements and searches for new physics. This white paper outlines the CEPC's discovery potential, including studies of exotic decays of the Higgs, Z, and top quarks, dark matter and dark sector phenomena, long-lived particles, supersymmetry, and neutrino-related signatures. Advanced detector technologies and reconstruction techniques, such as one-to-one correspondence reconstruction and jet origin identification, significantly improve sensitivity to rare and weakly interacting processes. The CEPC is particularly well suited to probe the electroweak phase transition and test models of electroweak baryogenesis and dark sector interactions. In addition, global fit analyses highlight the CEPC's complementary role in constraining a wide range of new physics scenarios. These features position the CEPC as a powerful tool for exploring the next frontier in fundamental particle physics in the post-Higgs discovery era.

hep-ex↗

arXiv2025

Self-interaction effects on the Kerr black hole superradiance and their observational implications

Through the black hole (BH) superradiance, ultralight bosons can form dense clouds around rotating Kerr BHs. Certain ultralight bosons, such as axions and axion-like particles (promising dark matter candidates), naturally possess self-interactions, and thus may significantly modify the dynamics of the superradiance process. Previous studies on the detection or constraint of ultralight bosons through superradiance have usually neglected the self-interaction effects of bosons. In this work, we investigate the formation and evolution of self-interacting boson clouds in the full Kerr spacetime during BH superradiance. Using numerical methods, we compute the superradiant growth rate of boson clouds with self-interactions around Kerr BHs and quantitatively evaluate how the self-interaction strength of scalar bosons affects the growth rate. We also assess the evolution of the BH's mass and spin. Our results reveal that, in addition to the superradiance-imposed upper bound on the boson cloud mass, self-interaction of ultralight bosons introduces a new, lower critical mass limit, beyond which the growth rate of the boson cloud approaches zero. This implies that the superradiance process terminates earlier when self-interaction is considered. Furthermore, we explore how self-interaction affects both the oscillation frequency of boson clouds in gravitational atoms and the frequency of gravitational wave (GW) emitted through cloud annihilation. The anticipated frequency shift might be detectable by the GW observatories. Given that self-interaction substantially alters the evolution of BH superradiance, its effects can significantly relax existing constraints on scalar bosons derived from superradiance. Taking the spin measurements from GW190412 and GW190517 as examples, we discuss the impact of self-interaction on constraint results in details.

hep-ph↗

arXiv2025

Pseudo-Goldstone Dark Matter from Primordial Black Holes: Gravitational Wave Signatures and Implications for KM3-230213A Event at KM3NeT

In many well-motivated new physics models, the pseudo-Nambu-Goldstone boson (pNGB) from U(1) symmetry breaking emerges as a promising dark matter candidate. Its coupling, suppressed by the symmetry breaking scale, prevents thermal equilibrium in the early Universe for high scale symmetry breaking. Thus, pNGB dark matter is predominantly produced via non-thermal mechanisms, such as the freeze-in process through a new portal coupling. In this work, we explore a novel mechanism for the production of pNGB dark matter even with feeble Higgs portal coupling-arising from Hawking radiation or superradiance of primordial black holes. We systematically investigate the production of light and heavy pNGB dark matter, both for Schwarzschild and Kerr black holes. We also discuss its potential gravitational wave signatures from domain wall collapse, density perturbations, and Hawking radiation. If the ultraviolet (UV) model is considered, the recent $\mathcal{O}$(100) PeV neutrino event KM3-230213A at KM3NeT can be naturally explained.

hep-ph↗

arXiv2025

Detectability of the Phase Transition Gravitational Waves in the DFSZ axion Model

In recent years, an increasing number of studies have focused on using gravitational waves to explore axions and the dynamics of Peccei-Quinn symmetry breaking at high energy scales in the early universe. To accurately quantify the capability of specific gravitational wave experiments to probe the axion properties, it is crucial to perform precise calculations of gravitational wave signals based on given axion models and to conduct detailed detectability analysis tailored to the experimental configurations. Therefore, in this work, we consider the widely-studied DFSZ axion model and, for the first time, perform precise calculations of the phase transition dynamics parameters and associated gravitational wave signals. Our results demonstrate that the DFSZ model allows a strong first-order phase transition for the Peccei-Quinn symmetry-breaking process at high energy scales exceeding $10^{9}~\mathrm{GeV}$. Moreover, by calculating the signal-to-noise ratio of the gravitational waves and comparing it with the thresholds of the Cosmic Explorer detector, we find that these signals are observable by the Cosmic Explorer with the energy scale range from $10^9~\mathrm{GeV}$ to $10^{12}~\mathrm{GeV}$. Notably, through Fisher Matrix analysis, we find that if Cosmic Explorer detectors observe these gravitational waves, the bubble wall velocity will be the first parameter to be determined. This study demonstrates that gravitational wave detection offers a powerful approach to investigating axion dynamics complementary to other experiments.

hep-ph↗

arXiv2025

Fundamental Physics and Cosmology with TianQin

The exploration of the surrounding world and the universe is an important theme in the legacy of humankind. The detection of gravitational waves is adding a new dimension to this grand effort. What are the fundamental physical laws governing the dynamics of the universe? What is the fundamental composition of the universe? How has the universe evolved in the past and how will it evolve in the future? These are the basic questions that press for answers. The space-based gravitational wave detector TianQin will tune in to gravitational waves in the millihertz frequency range ($10^{-4} \sim 1$ Hz, to be specific), opening a new gravitational wave spectrum window to explore many of the previously hidden sectors of the universe. TianQin will discover many astrophysical systems, populating the universe at different redshifts: some will be of new types that have never been detected before, some will have very high signal-to-noise ratios, and some will have very high parameter estimation precision. The plethora of information collected will bring us to new fronts on which to search for the breaking points of general relativity, the possible violation of established physical laws, the signature of possible new gravitational physics and new fundamental fields, and to improve our knowledge on the expansion history of the universe. In this white paper, we highlight the advances that TianQin can bring to fundamental physics and cosmology.

gr-qc↗

arXiv2025

Progress of the TianQin project

TianQin is a future space-based gravitational wave observatory targeting the frequency window of $10^{-4}$ Hz $\sim 1$ Hz. A large variety of gravitational wave sources are expected in this frequency band, including the merger of massive black hole binaries, the inspiral of extreme/intermediate mass ratio systems, stellar-mass black hole binaries, Galactic compact binaries, and so on. TianQin will consist of three Earth orbiting satellites on nearly identical orbits with orbital radii of about $10^5$ km. The satellites will form a normal triangle constellation whose plane is nearly perpendicular to the ecliptic plane. The TianQin project has been progressing smoothly following the ``0123" technology roadmap. In step ``0", the TianQin laser ranging station has been constructed and it has successfully ranged to all the five retro-reflectors on the Moon. In step ``1", the drag-free control technology has been tested and demonstrated using the TianQin-1 satellite. In step ``2", the inter-satellite laser interferometry technology will be tested using the pair of TianQin-2 satellites. The TianQin-2 mission has been officially approved and the satellites will be launched around 2026. In step ``3", i.e., the TianQin-3 mission, three identical satellites will be launched around 2035 to form the space-based gravitational wave detector, TianQin, and to start gravitational wave detection in space.

gr-qc↗

arXiv2025

The First Particles

After cosmic inflation, the universe is cold and almost empty. Thus, the inflation field should decay to the particles for BBN through the so-called reheating process. Later, the matter-antimatter asymmetry and dark matter are produced. In this chapter, the ``first particle" production between the inflation phase and BBN phase is introduced. We focus on the reheating, electroweak baryogenesis, and leptogenesis.

hep-ph↗