arXiv subjects

Yue-Liang Wu

Publications and source records attributed to Yue-Liang Wu.

At least 37 records · Page 2Linked to original sources

arXiv2025

Gravitational Wave Generation and Detection in Gravitational Quantum Field Theory

We investigate the production and detection of gravitational waves (GWs) within the framework of Gravitational Quantum Field Theory (GQFT). In this theory, GWs exhibit five propagating modes: one scalar, two vector, and two tensor modes. Unlike General Relativity, the gravitational field equations in GQFT involve both symmetric and antisymmetric tensors, governed by their respective energy-momentum tensors, both of which can act as sources for GW radiation. By solving the linearized gravitational equations, we derive general analytic expressions for the different GW degrees of freedom. Our analysis reveals that the symmetric energy-momentum tensor generates scalar and tensor GWs through the trace and traceless parts of the quadrupole moment, respectively. In contrast, the antisymmetric stress tensor induces scalar and vector GWs with enhanced coupling strengths. We examine two illustrative examples: a black hole binary with a slightly elliptical orbit, which produces scalar GWs, and a neutron star binary where one component has a net spin aligned with its velocity, leading to vector GW emission. Finally, we study the detectability of these GW polarizations by analyzing their signatures in GW detectors. Our findings indicate that current observatories can detect both scalar and tensor modes, while a newly designed detector would be required to probe vector GWs.

gr-qc↗

arXiv2025

A general theory of the standard model and the revelation of the dark side of the universe

A General Theory of the Standard Model (GSM) is built in a spin-related gravigauge spacetime, based on the conformal inhomogeneous spin gauge symmetry WS$_c$(1,3)=SP(1,3)$\rtimes$W$^{1,3}$$\rtimes$SP$_c$(1,1) and the scaling gauge symmetry SG(1), alongside the Standard Model symmetry U$_Y$(1)$\times$SU$_L$(2)$\times$SU(3)$_c$. This framework introduces novel interactions, including spin gauge force, chirality boost-spin force, chiral conformal-spin force, and scaling gauge force. A gravitization equation is derived to describe the gravitational effects arising from the non-commutative derivative operator in gravigauge spacetime. Within the Gravitational Quantum Field Theory (GQFT), the gravitational interaction is mediated by the gravigauge field, identified as the massless graviton. Both gauge-type and geometric-type gravitational equations are established, extending the description of gravidynamics beyond general relativity. A massive chirality boost-spin gauge boson, referred to as the dark graviton, emerges as a dark matter candidate, interacting with leptons and quarks via a spin gauge boson. Additionally, the fundamental scalar fields serve as sources of primordial energy and dark energy, driving early cosmic inflation and the current accelerated expansion of the universe.

physics.gen-ph↗

arXiv2025

Revisiting the fermionic quasi-bound states around Schwarzschild black holes with improved analytic spectrum

Black holes have long served as a testing ground for probing theories of gravity and quantum mechanics. Notably, fundamental fields in the neighborhood of black holes exhibit rich phenomena that could yield astrophysical observable signatures. However, exploring these structures typically requires computationally intensive numerical calculations. In this work, the dynamics of a massive Dirac field outside a Schwarzschild black hole is revisited. We propose a novel matching scheme that enables the analytical solution of the coupled first-order Dirac equation, as opposed to the conventional second-order approach. This method yields a compact and unified analytical expression for the energy spectrum, which shows improved agreement with numerical results. The improvement is due to high-order correction of angular parameter that has been ignored previously.

gr-qc↗

arXiv2025

Probing Dark Matter Spike with Gravitational Waves from Early EMRIs in the Milky Way Center

Cold dark matter may form dense structures around supermassive black holes (SMBHs), significantly influencing their local environments. These dense regions are ideal sites for the formation of extreme mass-ratio inspirals (EMRIs), in which stellar-mass compact objects gradually spiral into SMBH, emitting gravitational waves (GWs). Space-based gravitational-wave (GW) observatories such as LISA and Taiji will be sensitive to these signals, including early-stage EMRIs (E-EMRIs) that persist in the low-frequency band for extended periods. In this work, we investigate the impact of dark matter-induced dynamical friction on E-EMRIs in the Milky Way Center, model its effect on the trajectory, and calculate the resulting modifications to the GW spectrum. Our analysis suggests that this influence might be sizable and lead to detectable deviations in the spectrum, namely suppression at low frequencies and enhancement at high frequencies, therefore providing a potential probe for dark matter with future GW detectors in space, such as LISA and Taiji.

astro-ph.GA↗

arXiv2025

Identify hadron anomalous couplings at colliders

We investigate the identification of the Wess-Zumino-Witten (WZW) Lagrangian at colliders such as BESIII and the Super-$τ$-Charm Facility. Our analysis concentrates on the radiative decays of $η$ and $η'$ mesons, including $η^{(\prime)} \to γγ$, $η^{(\prime)} \to γ\ell^+ \ell^-$, $η^{(\prime)} \to π^+π^-γ$, and $η^{(\prime)} \to π^+π^-\ell^+\ell^-$, as well as semileptonic kaon decays such as $K^+ \to π^+π^- e^+ ν_e$. Employing the hidden local symmetry framework to incorporate vector meson contributions, we compute the decay amplitudes and form factors. For the decay $η\to π^+π^-γ$, the box anomaly dominates, and we find that the anomalous coupling can be experimentally determined to percent-level precision at BESIII. In contrast, vector meson contributions are significant in the decay $η' \to π^+π^-γ$. Using experimental data for $η' \to π^+π^-γ$, we obtain ${\cal B}_{\mathrm{box}}^{\text{exp}} = (1.70 \pm 0.05)\%$, which is approximately ten times larger than previously expected experimentally. We observe good agreement between our calculated anomalous couplings and experimental results. In kaon decays, WZW terms uniquely contribute to the form factor $H$, which can be extracted from parity-conserving decay distributions. While predictions at the chiral point closely match experimental values (e.g., $H^+ = -2.31$ versus $-2.27 \pm 0.10$), we find that intermediate vector meson states introduce substantial corrections, potentially as large as 25%. We strongly advocate for revisiting these experiments to achieve improved precision in form factor extractions.

hep-ph↗

arXiv2025

Intermediate-mass-ratio inspirals with general dynamical friction in dark matter minispikes

The intermediate-mass-ratio inspirals (IMRIs) may be surrounded by dark matter (DM) minispikes. The dynamical friction from these DM minispike structures can affect the dynamics and the gravitational wave (GW) emission of the IMRIs. We analyze the effects of general dynamical friction, with a particular contribution from DM particles moving faster than the stellar-mass black hole in an eccentric IMRI. Our calculation show that these DM particles tends to eccentricify the orbit, therefore the evolution of the eccentricity depends on the competition between the fast moving DM particles and the slow moving DM particles. The results show that the dynamical friction enhances the eccentricity when $γ_\mathrm{sp}\lesssim2.0$, and the general dynamical friction is able to increase the eccentricity. We also analyze the effects of general dynamical friction on the GW characteristic strain. The results indicate that the characteristic strain is suppressed at lower frequencies, and the peak value of the characteristic strain occurs at higher frequencies as the power law index of DM minispike $γ_\mathrm{sp}$ increases. For the first time, a relation between the frequency peak value of characteristic strain of GWs and $γ_\mathrm{sp}$ is established. Using this analytical relation, the presence of DM and its halo density may be determined potentially from future GW data.

astro-ph.HE↗

arXiv2025

Probing Hadron-quark Transition Through Binary Neutron Star Merger

The cores of massive neutron stars offer a unique environment for the nuclear matter at intermediate density in the universe. The global characteristics of a neutron star, as well as the gravitational waves emitted from the mergers of two neutron stars, offer valuable insights into dense nuclear matter. In this paper, we comprehensively investigate the effect of the potential hadron-quark transition on the properties of neutron stars and the signals of the gravitational waves stemming from the merger of binary neutron stars, including waveforms, frequency evolutions as well as the spectrum curves, utilizing the equations of state constructed from the Maxwell ansatz, Gibbs ansatz and, the crossover scenario. We explicitly construct the equations of state in such a way that they converge at low and high densities therefore the differences are only from the scenarios of the transitions and the locations -- or the parameters in the equation of state. Using such constructed equations of state, we simulate the signals of the gravitational wave (GW) and analyze their differences due to locations of the transition, the scenarios of the transition, and the masses of the component stars. We find that (1) in both the Maxwell ansatz and Gibbs ansatz, GW signals are sensitive to the location and the latent heat of the phase transition, (2) in the post-merger phase, the frequency of GW increases with the evolution in Maxwell type transition but is stable in the other two types of transitions and, (3) the amount of radiated energy is the biggest in Gibbs construction (GC) type transition and the smallest in the crossover construction (CC) type transition. By combining our findings with the expected detection of gravitational waves around $(2$-$4)$ kHz from binary neutron star mergers and their associated electromagnetic signals, we expect to uncover some key characteristics of dense nuclear matter.

astro-ph.HE↗

arXiv2024

A holographic study on QCD phase transition and neutron star properties

We investigate the QCD phase transition and its phase structure within Einstein-Maxwell-Dilaton-scalar system and compare the results with those obtained from the Einstein-Maxwell-Dilaton system. It is shown that both models reproduce behavior consistent with lattice QCD. In particular, the Einstein-Maxwell-Dilaton-scalar system exhibits a first-order phase transition in the pure gauge sector, aligning with predictions from Yang-Mills theory. Based on these models, we construct a holographic model for neutron stars, incorporating leptons to satisfy electric charge neutrality, and examine the cold equation of state, the mass-radius relation, and tidal deformability of neutron stars. It is demonstrated that the Einstein-Maxwell-Dilaton-scalar system enables us to describe neutron star properties that meet current astrophysical constraints.

hep-ph↗

arXiv2024

Beam quality $M^2(ψ)$ factor, spot rotation angle, and angular speed in general laser beams

A unified definition for the rotation angle and rotation angular speed of general beams, including those with orbital angular momentum (OAM), has been lacking until now. The rotation of a general beam is characterized by observing the rotational behavior of the directions of the extreme spot sizes during propagation. We introduce the beam quality $M^2(ψ)$ factor to characterize the unique beam quality of a general beam across all directions, not limited to the $x$- or $y$-axes. Besides that, we present the beam center $s_ψ(ψ,z)$, spot size $w_ψ(ψ,z)$, waist position, waist radius, and divergence angle along the direction that forms an angle $ψ$ with the $x$-axis in the plane perpendicular to the $z$-axis for the general beam. Furthermore, this paper presents rapid calculation formulas for these parameters, utilizing the mode expansion method (MEM). Subsequently, we prove that only two extreme spot sizes exist in a given detection plane and the angle between the maximum and minimum spot angles is consistently $90^{\circ}$ during the propagation. We also prove the spot rotation angles converge as $z$ approaches either positive or negative infinity. We first show the extreme spot sizes, spot rotation angle, and angular speed for the vortex beam. Our formulas efficiently differentiate between vortex OAM beams and asymmetry OAM beams.

physics.optics↗

arXiv2024

Approximate model for the coupling of far-field wavefront errors and jitter in space-based gravitational wave laser interferometry

Space-based gravitational wave observatories, such as LISA, Taiji, and TianQin, employ long-baseline laser interferometry, necessitating displacement measurement sensitivity at 1 pm/$\sqrt{Hz}$ level. A significant challenge in achieving this precision is the coupling noise arising from far-field wavefront errors (WFE) and laser pointing jitter. This paper presents a comprehensive noise model that incorporates three critical factors: transmitted WFE, static pointing angle, and laser beam jitter. Utilizing the Nijboer-Zernike diffraction theory, we derive an approximate expression for far-field WFE, ensuring minimal error and efficient computational performance. The approximate expression has convincing physical interpretability and reveals how various Zernike aberrations and their coupling impact far-field WFE. Furthermore, the study identifies that correcting optical axis deviations induced by $Z_3^{\pm1}$ through beam tilt exacerbates far-field WFE, underscoring the necessity for active suppression of $Z_3^{\pm1}$. The proposed model facilitates detailed system simulations of the laser link, evaluates Tilt-to-Length (TTL) noise, and offers theoretical insights for system optimization.

astro-ph.IM↗

arXiv2024

Sky location of Massive Black Hole Binaries in the foreground of Galactic white dwarf binaries

For space-based gravitational wave (GW) detection, the main noise source for massive black hole binaries (MBHBs) is attributed to approximately $10^7$ double white dwarf binaries in the foreground. For a GW source, the amplitude of the detector response, recorded by a space-based gravitational wave detector, exhibits a modulation effect with a year period when observing the source from various orbital positions. Under the adverse conditions mentioned above, where there is a strong foreground noise and annual modulation in the signals, we employed the wavelet transform and the strong-amplitude relevant orbital position search methods, which allows the weak MBHB sources to achieve higher locating accuracy. In detail, for two MBHB sources of lower intensity, the precision of luminosity distance, represented by the ratio $ΔD_L / D_L$ at the 95$\%$ confidence level, is enhanced by factors of $\sim$ 2. And the angular resolutions, denoted by $ΔΩ_s$, are enhanced by a factor of $\sim$ 20. These improvements increase the number of detectable GW sources, facilitates multi-messenger follow-up observations and provides constraints on the cosmological constant.

astro-ph.HE↗

arXiv2024

Detecting Ultralight Dark Matter Gravitationally with Laser Interferometers in Space

Ultralight dark matter (ULDM) is one of the leading well-motivated dark matter candidates, predicted in many theories beyond the standard model of particle physics and cosmology. There have been increasing interests in searching for ULDM in physical and astronomical experiments, mostly assuming there are additional interactions other than gravity between ULDM and normal matter. Here we demonstrate that even if ULDM has only gravitational interaction, it shall induce gravitational perturbations in solar system that may be large enough to cause detectable signals in future gravitational-wave (GW) laser interferometers in space. We investigate the sensitivities of Michelson time-delay interferometer to ULDM of various spins, and show vector ULDM with mass $m\lesssim 10^{-18}~$eV can be probed by space-based GW detectors aiming at $μ$Hz frequencies. Our findings exhibit that GW detectors may directly probe ULDM in some mass ranges that otherwise are challenging to examine.

hep-ph↗

arXiv2024

Sky location of Galactic white dwarf binaries in space-based gravitational wave detection

Quickly localizing the identified white dwarf (WD) binaries is the basic requirement for the space-based gravitational wave (GW) detection. In fact, the amplitude of GW signals are modulated by the periodic motion of GW detectors on the solar orbit. The intensity of the observed signals is enhanced according to the observation time beyond a year to enhance a high signal to noise ratio (SNR). As data gap exists, the completeness of the data observed for a long time depends on filling gaps in the data. Actually, in a year period, the GW sources have a best observation orbit position of GW detectors, where the detector response intensity of GW is maximum. Thus, the best positions, where the direction of GW source is perpendicular to the detection arms, can be searched for the verified GW sources of the sky map to enhance SNR too. For the three arms response intensity of the GW signals changing more clearly with the location of the GW sources relative to the detector, the noises and the suppression of noise by time delay interferometer are ignored. In the four chosen sources, the two verification WD binaries: J0806 and V407 Vul are observed at the best orbit positions by TAIJI for the short time of 2 and 3 days respectively. The intensities of those GWs are above the values of the TAIJI sensitivity curve, significantly. Compared with a single detector, the network of two detectors does not significantly improve the accuracy of location of the verification binaries. These results imply that the searching of GW signals and parameter estimation of GW sources from the experimental data of the space-based mission do not ignore the orbit positions relevant to GW sources.

gr-qc↗

arXiv2024

Linear dynamics and classical tests of the gravitational quantum field theory

We explore the new physics phenomena of gravidynamics governed by the inhomogeneous spin gauge symmetry based on the gravitational quantum field theory. Such a gravidynamics enables us to derive the generalized Einstein equation and an equation beyond it. To simplify the analyses, we linearize the dynamic equations of gravitational interaction by keeping terms up to the leading order in the dual gravigauge field. We then apply the linearized dynamic equations into two particular gravitational phenomena. First, we consider the linearized equations in the absence of source fields, which is shown to have five physical propagating polarizations as gravitational waves, i.e., two tensor modes, two vector modes, and one scalar, instead of two tensor polarizations in the general relativity. Second, we examine the Newtonian limit in which the gravitational fields and the matter source distribution are weak and static. By deriving the associated Poisson equation, we obtain the exact relation of the fundamental interaction coupling in the gravidynamics with the experimentally measured Newtonian constant. We also make use of nonrelativistic objects and relativistic photons to probe the Newtonian field configurations. In particular, the experiments from the gravitational deflection of light rays and the Shapiro time delay can place stringent constraints on the linearized gravidynamics in the gravitational quantum field theory.

gr-qc↗

arXiv2023

A holographic study on QCD phase transition and phase diagram with two flavors

We investigate the chemical potential effects of the equation of state and the chiral transition in an Einstein-Maxwell-dilaton-scalar system, which is obtained from an improved soft-wall AdS/QCD model coupled with an Einstein-Maxwell-dilaton system. The equations of state obtained from the model are in quantitative agreement with the lattice results at both zero and nonzero chemical potentials. The sensible chiral transition behaviors can be realized in the model. The QCD phase diagram with a CEP has also been obtained from the model.

hep-ph↗

arXiv2023

Taiji Data Challenge for Exploring Gravitational Wave Universe

The direct observation of gravitational waves (GWs) opens a new window for exploring new physics from quanta to cosmos and provides a new tool for probing the evolution of universe. GWs detection in space covers a broad spectrum ranging over more than four orders of magnitude and enables us to study rich physical and astronomical phenomena. Taiji is a proposed space-based GW detection mission that will be launched in the 2030s. Taiji will be exposed to numerous overlapping and persistent GW signals buried in the foreground and background, posing various data analysis challenges. In order to empower potential scientific discoveries, the Mock LISA Data Challenge and the LISA Data Challenge (LDC) were developed. While LDC provides a baseline framework, the first LDC needs to be updated with more realistic simulations and adjusted detector responses for Taiji's constellation. In this paper, we review the scientific objectives and the roadmap for Taiji, as well as the technical difficulties in data analysis and the data generation strategy, and present the associated data challenges. In contrast to LDC, we utilize second-order Keplerian orbit and second-generation time delay interferometry techniques. Additionally, we employ a new model for the extreme-mass-ratio inspiral waveform and stochastic GW background spectrum, which enables us to test general relativity and measure the non-Gaussianity of curvature perturbations. Furthermore, we present a comprehensive showcase of parameter estimation using a toy dataset. This showcase not only demonstrates the scientific potential of the Taiji Data Challenge but also serves to validate the effectiveness of the pipeline. As the first data challenge for Taiji, we aim to build an open ground for data analysis related to Taiji sources and sciences. More details can be found on the official website at http://taiji-tdc.ictp-ap.org.

gr-qc↗

arXiv2023

Sensitivity of Space-based Gravitational-Wave Interferometers to Ultralight Bosonic Fields and Dark Matter

Ultralight bosonic fields (ULBFs) are predicted by various theories beyond the standard model of particle physics and are viable candidates of cold dark matter. There have been increasing interests to search for the ULBFs in physical and astronomical experiments. In this paper, we investigate the sensitivity of several planned space-based gravitational-wave interferometers to ultralight scalar and vector fields. Using time-delay interferometry (TDI) to suppress the overwhelming laser frequency noise, we derive the averaged transfer functions of different TDI combinations to scalar and vector fields, and estimate the impacts of bosonic field's velocities. We obtain the sensitivity curves for LISA, Taiji and TianQin, and explore their projected constraints on the couplings between ULBFs and standard model particles, illustrating with the ULBFs as dark matter.

gr-qc↗

arXiv2023

On networks of space-based gravitational-wave detectors

The space-based laser interferometers, LISA, Taiji and TianQin, are targeting to observe milliHz gravitational waves (GWs) in the 2030s. The joint observations from multiple space-based detectors yield significant advantages. In this work, we recap the studies and investigations for the joint space-based GW detector networks to highlight: 1) the high precision of sky localization for the massive binary black hole (BBH) coalescences and the GW sirens in the cosmological implication, 2) the effectiveness to test the parity violation in the stochastic GW background observations, 3) the efficiency of subtracting galactic foreground, 4) the improvement in stellar-mass BBH observations. We inspect alternative networks by trading off massive BBH observations and stochastic GW background observation.

gr-qc↗