arXiv subjects

Wenjun Guo

Publications and source records attributed to Wenjun Guo.

10 recordsLinked to original sources

arXiv2026

Black hole correspondences of quasi-topological gravity : Shadows, quasinormal modes, graybody factors

Within the framework of quasi-topological gravity, we systematically investigate the correspondences among three classes of observables---the shadow, the quasinormal modes, and the graybody factors---of regular black holes in $D = 5$ dimensions. Using the WKB approximation and GrayHawk numerical integration, we test the applicability of the GBF--QNM correspondence and the shadow--GBF correspondence in the low-mode ($l=2$) and higher-dimensions ($D=5$): the difference between the GBF--QNM correspondence and the numerical results remains small in magnitude; we apply the known Langer correction (replacing $l$ by the effective angular momentum $\kappa = \sqrt{l(l+D-3)} \simeq l + (D-3)/2$), which reduces the error of the shadow--GBF correspondence at low modes to a level comparable with that of the GBF--QNM correspondence. Our work extends the shadow--GBF correspondence to higher-dimensional regular black holes, providing a viable route to predict the black hole spectrum and the Hawking radiation profile from a single observable, and thereby to realize multi-messenger tests of gravity.

gr-qc↗

arXiv2025

Modeling the Mental World for Embodied AI: A Comprehensive Review

As the application of Embodied AI Agents in avatars, wearable devices, and robotic systems continues to deepen, their core research challenges have gradually shifted from physical environment interaction to the accurate understanding of social interactions. Traditional physical world models (PWM) focus on quantifiable physical attributes such as space and motion, failing to meet the needs of social intelligence modeling. In contrast, the Mental World Model (MWM), as a structured representation of humans' internal mental states, has become the critical cognitive foundation for embodied agents to achieve natural human-machine collaboration and dynamic social adaptation. However, current MWM research faces significant bottlenecks: such as fragmented conceptual framework with vague boundaries between MWM and PWM, disjointed reasoning mechanisms for the technical pathways and applicable scenarios of different Theory of Mind (ToM) reasoning paradigms, and detachment between evaluation and practice. To address these issues, this review systematically synthesizes over 100 authoritative studies to provide a comprehensive overview of MWM research for embodied AI. Its core contributions are threefold: First, it constructs a complete theoretical framework for MWM for the first time. Specifically, it distinguishes the essential differences between MWM and PWMs. Second, it systematically defines the key components of MWM through two paradigms for mental element representation. Third, it comprehensively analyzes two core ToM reasoning paradigms with 19 ToM methods. Finally, it also clarifies the integration trend of neuro-symbolic hybrid architectures, and synthesizes 26 ToM evaluation benchmarks. This work aims to promote the integration of embodied agents into human society and advance the in-depth development of human-machine collaborative interaction.

cs.RO↗

arXiv2025

Graybody factors and absorption cross-sections of non-exchange black holes in Instein-coupled scalar fields

This paper studies scalar field perturbations coupled with Einstein tensors of non-exchange black holes. We use the polarization method to calculate graybody factors and absorption cross-sections selected by different parameters, and verify the latest correspondence between graybody factors and quasi-normal states. The results show that the larger the value of the non-exchange parameter $\theta$ and the coupling constant $\eta$ introduced into the model, the smaller the absorption cross-section. Furthermore, we found that this correspondence is accurate for non-commutative black holes at the $1$ limit of large angular momentum quantum numbers.

gr-qc↗

arXiv2025

Geodesic structure of a noncommutative black hole

This paper explores the metric of Piero Nicolini's noncommutative black hole spacetime, calculates its effective potential, and presents the corresponding potential curve. By analyzing this curve, we identify various orbit types for test particles and photons in this spacetime. Using the dynamical equations for particles and photons near the black hole, we plot the specific time-like and null geodesic structures. We analyze the impact of different values of the total mass of the source $M$ and angular momentum $L$ on time-like geodesics. Our results indicate that in the Piero black hole spacetime, increases in total mass and angular momentum reduce the perihelion precession rate of the orbit. Notably, the effect of total mass is nonlinear, while the effect of angular momentum is linear.

gr-qc↗

arXiv2023

Different Regular Black Holes: Geodesic Structures of Test Particles

This paper investigates the metric of previously proposed regular black holes, calculates their effective potentials, and plots the curves of the effective potentials. By determining the conserved quantities, the dynamical equations for particles and photons near the black hole are derived. The analysis encompasses timelike and null geodesics in different spacetimes, including bound geodesics, unstable circular geodesics, stable circular geodesics, and escape geodesics. The findings are presented through figures and tables. Furthermore, the bound geodesics of the four regular black hole spacetimes are analyzed, examining the average distance of particle orbits from the center of the event horizon, the precession behavior of the perihelion, and the probability of particles appearing inside the outer event horizon during motion. Based on these analyses, a general formula is proposed, which yields the existing metrics when specific parameter values are chosen. The impact of parameter variations on the effective potential and geodesics is then computed using this new formula.

gr-qc↗

arXiv2023

Effects of Phi and $\sigma^{*}$-meson on properties of hyperon stars including $\Delta$ resonance

In this work, we study the properties of neutron stars using the linear Relativistic Mean-Field (RMF) theory and consider multiple degrees of freedom inside neutron stars, including hyperons and $\Delta$ resonances. We investigate different coupling parameters $x_{\sigma \Delta}$ between $\Delta$ resonances and nucleons and compare the differences between neutron stars with and without strange mesons $\sigma^*$ and $\phi$. These effects include particle number distributions, equations of state (EOS), mass-radius relations, and tidal deformabilities. To overcome the "hyperon puzzle," we employ the $\sigma-cut$ scheme to obtain neutron stars with masses up to $2M_{\odot}$. We find that strange mesons appear at around 3$\rho_0$ and reduce the critical density of baryons in the high-density region. With increasing coupling parameter $x_{\sigma \Delta}$, the $\Delta$ resonances suppress hyperons, leading to a shift of the critical density towards lower values. The early appearance of $\Delta$ resonances may play a crucial role in the stability of neutron stars. Strange mesons soften the EOS slightly, while $\Delta$ resonances predominantly soften the EOS in the low-density region. By calculating tidal deformabilities and comparing with astronomical observation GW170817, we find that the inclusion of $\Delta$ resonances decreases the radius of neutron stars.

nucl-th↗

arXiv2022

Kaon-meson condensation and $\Delta$ resonance in hyperonic stellar matter within a relativistic mean-field model

We study the equation of state of dense baryon matter within the relativistic mean-field model, and we include ${\Delta}$(1232) isobars into IUFSU model with hyperons and consider the possibility of kaon meson condensation. We find that it is necessary to consider the $\Delta$ resonance state inside the massive neutron star. The critical density of Kaon mesons and hyperons is shifted to a higher density region, in this respect an early appearance of $\Delta$ resonances is crucial to guarantee the stability of the branch of hyperonized star with the difference of the coupling parameter $x_{\sigma \Delta}$ constrained based on the QCD rules in nuclear matter. The $\Delta$ resonance produces a softer equation of state in the low density region, which makes the tidal deformability and radius consistent with the observation of GW170817. As the addition of new degrees of freedom will lead to a softening of the equation of state, the ${\sigma}$-cut scheme, which states the decrease of neutron star mass can be lowered if one assumes a limited decrease of the ${\sigma}$-meson strength at ${\rho_B}$($\rho_B > \rho_0$), finally we get a maximum mass neutron star with $\Delta$ resonance heavier than 2$M_{\odot}$.

nucl-th↗

arXiv2022

Kaon meson condensate in neutron star matter including hyperons

The recent measurement of the mass of neutron stars (PSR J1614 - 2230, PSR J0348 + 0432, MSP J0740 + 6620) restricts the lower limit $\sim 2M_{\odot}$ of the maximum mass of such compact stars, making it possible for dense matter to exist in massive stars. The relativistic mean field theory with parameter sets FSUGold including Kaon condensation is used to describe the properties of neutron stars in $β$ equilibrium. Through careful choice of the parameter of the $σ$-cut $c_σ$, we are able to produce a maximum mass neutron star with Kaon condensation heavier than $2M_{\odot}$, and we find that the parameter $Λ_ν$ of the $ρ-ω$ interaction term in this model has a significant effect on $K^{-}$ condensation. In the case of using $σ$-cut scheme, $K^{-}$ condensation occurs only when the $ρ-ω$ interaction $Λ_ν$ is switched off.

nucl-th↗

arXiv2021

Quasinormal modes of scalar field coupled to Einstein's tensor in the non-commutative geometry inspired black hole

We investigate the quasinormal modes (QNMs) of the scalar field coupled to the Einstein's tensor in the non-commutative geometry inspired black hole spacetime. It is found that the lapse function of the non-commutative black hole metric can be represented by a Kummer's confluent hypergeometric function, which can effectively solve the problem that the numerical results of the QNMs are sensitive to the model parameters and make the QNMs values more reliable. We make a careful analysis of the scalar QNM frequencies by using several numerical methods, and find that the numerical results obtained by the new WKB method (the Padé approximants) and the Mashhoon method (P$\ddot{\text{o}}$schl-Teller potential method) are quite different from those obtained by the asymptotic iterative method (AIM) and time-domain integration method when the non-commutative parameter $θ$ and coupling parameter $η$ are large. The most obvious difference is that the numerical results obtained by the AIM and the time-domain integration method appear a critical value $η_c$ with an increase of $η$, which leads to the dynamical instability. After carefully analyzing the numeral results, we conclude that the numerical results obtained by the AIM and the time-domain integration method are closer to the theoretical values than those obtained by the WKB method and the Mashhoon method, when the $θ$ and $η$ are large. Moreover, through a numerical fitting, we obtain that the functional relationship between the threshold $η_c$ and the non-commutative parameter $θ$ satisfies $η_{c}=aθ^{b}+c$ for a fixed $l$ approximately. We find that the stability of dynamics can be ensured in the $η<η_c(θ, l)$ region.

nucl-th↗

arXiv2020

Scalar field quasinormal modes of noncommutative high dimensional Schwarzschild-Tangherlini black hole spacetime with smeared matter sources

We investigate the massless scalar quasinormal modes (QNMs) of the noncommutative $D$-dimensional Schwarzschild-Tangherlini black hole spacetime in this paper. By using the Wentzel-Kramers-Brillouin (WKB) approximation method, the asymptotic iterative method (AIM) and the inverted potential method (IPM) method, we made a detail analysis of the massless scalar QNM frequencies by varying the general smeared matter distribution and the allowable characteristic parameters ($k$ and $θ$) corresponding to different dimensions. It is found that the nonconvergence of the high order WKB approximation exists in the QNMs frequencies of scalar perturbation around the noncommutative $D$-dimensional Schwarzschild black holes. We conclude that the 3rd WKB result should be more reliable than those of the high order WKB method since our numerical results are also verified by the AIM method and the IPM method. In the dimensional range of $4\leq D \leq7$, the scalar QNMs as a function of the different papameters (the noncommutative parameter $θ$, the smeared matter distribution parameter $k$, the multipole number $l$ and the main node number $n$) are obtained. Moreover, we study the dynamical evolution of a scalar field in the background of the noncommutative high dimensional Schwarzschild-Tangherlini black hole.

gr-qc↗