arXiv subjects

Hong Guo

Publications and source records attributed to Hong Guo.

At least 73 records · Page 4Linked to original sources

arXiv2025

Quasibound States and Superradiant Instability of Black Hole in Analog Gravity

In this paper, we adopt continued fraction method (CFM) associated with VBK approach, which is recently developed by Vieira, Bezerra and Kokkotas, to investigate the spectrum of quasibound states (QBS) and superradiant instability of massive scalar perturbation imposed on analog rotating black hole in photon-fluid model. We analyze the effects of black hole angular velocity $Ω_H$ and scalar field mass $μ$ on QBS spectrum with positive and negative winding number $m=\pm1$, respectively. In addition to the fundamental frequency, we also investigate the overtones in order to disclose more distinctions of spectrum between the states of $m=\pm 1$. We show that the sign of winding number can produce notable impacts on the spectrum, particularly to the imaginary part of the spectrum. We study the superradiant instability and find that the maximum instability for a given $Ω_H$ is not in monotonic relationship with angular velocity, which is in contrast to the case in Kerr black hole spacetime. As expected, the strength of superradiant instability can be significantly weakened by increasing the winding number. These findings imply that there exists a critical angular velocity under which the instability is strongest in parameter space, and we are supposed to find it out at $m=1$. Indeed, this max instability is found to be $ω_{Imax}\approx 1.13374\times 10^{-5}$ related to the critical angular velocity $Ω_H\approx1.22$.

gr-qc↗

arXiv2025

Resource Allocation for Mutualistic Symbiotic Radio with Hybrid Active-Passive Communications

Mutualistic SR is a communication paradigm that offers high spectrum efficiency and low power consumption, where the SU transmits information by modulating and backscattering the PT's signal, enabling shared use of spectrum and power with PT. In return, the PT's performance can be enhanced by SU's backscattered signal, forming a mutualistic relationship. However, the low modulation rate causes extremely inferior transmission rates for SUs. To improve the SU transmission rate, this paper proposes a new mutualistic SR with HAPC to explore the tradeoff between BC and AC in terms of power consumption and transmission rate, enabling each SU to transmit signal via passive BC and AC alternatively. We propose two problems to maximize the total rate of all SUs under the fixed and dynamic SIC ordering, respectively. The fixed SIC ordering-based problem is to jointly optimize the SUs' reflection coefficients, the transmit power of each SU during AC, and the time allocation for each SU during BC and AC, subject to the energy causality constraint and the PT's transmission rate gain constraint. In addition to pondering the constraints involved in the fixed SIC ordering-based problem, the dynamic SIC ordering-based problem, which is a mixed integer programming one, further considers the SIC ordering constraint. The above two problems are solved by our proposed SCA-based and BCD-based iterative algorithms, respectively. Simulation results demonstrate that: 1) the proposed mutualistic SR system outperforms traditional designs in terms of the rates achieved by SUs under the same constraints; 2) the total rate of all SUs under the dynamic SIC ordering is larger than that of the fixed one when the PT's minimum rate gain is high, and becomes nearly identical when the PT's minimum rate gain is low.

cs.IT↗

arXiv2025

A Critical Point on the Hairy Black Hole Phase Boundary in the Improved Holographic Einstein-Maxwell-Dilaton Theory

In this work, we investigate the hairy black hole solutions and their dual phase diagram in the improved holographic Einstein-Maxwell-Dilaton (EMD) model.From the gravitational perspective, the rich phase structures observed in the dual boundary field theory originate from the intricate interplay between the scalar field formalism and the Maxwell field coupling mechanism. Two distinct types of hairy black hole solutions are found in this framework. Type-I hairy black holes are predominantly governed by scalar potential dynamics, whereas Type-II solutions emerge through nonminimal coupling to the $U(1)$ gauge field. We map out the phase distribution in the $(μ_B,T)$ parameter plane and delineate the boundary separating these two hairy phases. The phase diagram exhibits a first-order phase transition line consistent with previous findings, accompanied by a subtle third-order phase transition line that terminates at a critical point positioned at the turning point of the entire phase boundary curve. Our results complement existing research on holographic EMD theory by offering a comprehensive characterization of phase distributions, transition boundaries, and their gravitational sector interpretations. These insights will enable more effective engineering of specific phase structures for simulating strongly coupled systems through targeted modifications to the EMD model.

hep-th↗

arXiv2025

Negative potential-induced scalarization in the Einstein-Euler-Heisenberg black hole

We investigate a negative potential-induced scalarization of the Einstein-Euler-Heisenberg (EEH) black hole in the EEH-scalar (EEHS) theory, characterized by mass $M$, Euler-Heisenberg parameter $μ$, and magnetic charge $q$. Within this framework, the charge $q$ can exceed the extremal bound $q/M > 1$, and a single event horizon is maintained provided the parameter $μ$ exceeds the $μ_{\text{max}} = 0.019$, with the ADM mass fixed at $M = 1/2$. We obtain a single branch of scalarized EEH (sEEH) black holes for $q > 0$ which is considered as the simplest model for scalarization of EEH black holes. We found that this class of hairy black holes is not thermodynamically favored, and their quasinormal modes indicate they are dynamically unstable. An interesting feature is that when $q < 1/2$, the scalar charge varies only slightly with $q$ for a fixed mass. In contrast, for $q>1/2$, the scalar charge increases more rapidly as $q$ increases. This distinct behavior suggests that the scalar charge exhibits the characteristics of a primary charge for $q < 1/2$, and of a secondary charge for $q > 1/2$. This finding reveals notable features of hairy black holes in EEH theory, specifically in the overcharging regime.

gr-qc↗

arXiv2025

Parameter constraints on Horndeski rotating black hole through quasiperiodic oscillations

In this paper, we perform small perturbations around the circular timelike orbit in the equatorial plane of the Horndeski rotating black hole, and analyze the effects of Horndeski hair on the three fundamental frequencies of the epicyclic oscillations. Since this operation can model the quasiperiodic oscillations (QPOs) phenomena of the surrounding accretion disc, we then employ the MCMC simulation to fit the theoretical results with three QPO events, including GRO J1655-40, XTE J1859+226 and H1743-322, and constrain the characteristic radius $r$, black hole mass $M$ and spinning parameter $a$, and the Horndeski hair parameter $h$. Our constraint on the Horndeski hair parameter is much tighter than QPOs simulation from the existed accretion models, suggesting slight deviation from classical Kerr black hole.

gr-qc↗

arXiv2025

Investigating the residuals in the $M_\bullet-M_*$ relation using the SIMBA cosmological simulation

We study the scaling relation between the black hole and stellar mass ($M_\bullet-M_*$), diagnosing the residual $Δ\log(M_\bullet/M_\odot)$ ($Δ$) in this relation to understand the coevolution of the galaxy and black hole (BH) in the cosmological hydrodynamic simulation SIMBA. We showed that SIMBA can reproduce the observed $M_\bullet-M_*$ relation well with little difference between central and satellite galaxies. By using the median value to determine the residuals, we found that the residual is correlated with galaxy cold gas content, star formation rate, colour and black hole accretion properties. Both torque and Bondi models implemented in SIMBA, contribute to this residual, with torque accretion playing a major role at high redshift and low-mass galaxies, while Bondi (also BH merge) takes over at low redshift and massive galaxies. By dividing the sample into two populations: $Δ>0$ and $Δ<0$, we compared their evolution paths following the main progenitors. With evolution tracking, we proposed a simple picture for the BH-galaxy coevolution: Early-formed galaxies seeded black holes earlier, with stellar mass increasing rapidly to quickly reach the point of triggering `jet mode' feedback. This process reduced the cold gas content and stopped the growth of $M_*$, effectively quenching galaxies. Meanwhile, during the initial phase of torque accretion growth, the BH mass is comparable between galaxies formed early and those formed later. However, those galaxies that formed earlier appear to attain a marginally greater BH mass when shifting to Bondi accretion, aligning with the galaxy transition time. As the early-formed galaxies reach this point earlier -- leaving a longer time for them to have Bondi accretion as well as merging, their residuals become positive, i.e., having more massive BHs at $z=0$ compared to these late-formed galaxies at the same $M_*$. This picture is further supported by the strong positive correlation between the residuals and the galaxy age, which we are proposing as a verification with observation data on this story suggested by SIMBA.

astro-ph.GA↗

arXiv2025

Time-Frequency Transfer over Optical Fiber

Optical time-frequency transfer establishes the metrological linkage in large-scale clock networks, which facilitates various applications. Fiber-based transfer benefits from the abundant deployment of fiber infrastructures to achieve this advantage. In this Review, we provide an overview of the advances in optical two-way time-frequency transfer, which began with characterizing the time-frequency transfer stability. Then, we discuss the system configuration, key modules, main challenges, and mainstream transfer methods. Finally, the Review concludes with an outlook on further applications toward global-scale high-precision clock networks.

physics.optics↗

arXiv2025

Unveiling the galactic baryon cycle process by an empirical model

We propose an empirical model to describe and constrain the baryon cycle process during galaxy evolution. This model utilizes the evolution of star formation rate, derived from the stellar mass-halo mass relations (SHMRs) across different redshifts, and the cold gas content, derived from the NeutralUniverseMachine model, to constrain gas accretion and recycle of gas outflow in the model galaxy. Additionally, through detailed modeling of each cycle process, particularly the recycling process, and utilizing the gas-phase mass-metallicity relation (MZR) at $z=0$ as a constraint, our model establishes a relation between the recycle fraction and halo mass. It is found that the fraction of gas recycled from the outflow is a function of halo mass, with a value of $25\%$ in galaxies with halo mass $\sim10^{10.4}M_{\rm \odot}$, increasing to $75\%$ in halos with mass $\sim 10^{12}M_{\rm \odot}$. We also find that the mass loading factor from the FIRE-2 simulation matches well with the constraints from both observational data and our model. Furthermore, using the gas content and metallicity of the circumgalactic medium (CGM) obtained from hydrodynamical simulations as constraints, our model predicts that on average $70\%$ of universal baryon accretion is accreted to the halo and $80\%$ of the non-recycled gas in the outflow has escaped from the galaxy, entering the intergalactic medium (IGM). However, we note that future observational data are needed to finally constrain the mass and metal exchange between the CGM and the IGM.

astro-ph.GA↗

arXiv2025

Approaching the Key Rate Limit in Continuous-Variable Quantum Key Distribution Network

A quantum key distribution network enables pairs of users to generate independent secret keys by leveraging the principles of quantum physics. For end-to-end secure communication, a user pair's secret key must remain secure against any third parties, including both external eavesdroppers and other network users. However, isolating a given user pair from the remaining users while maintaining a high key rate is challenging when all users are intrinsically coupled and correlated, particularly in continuous-variable networks. This results in either a low key rate, or incomplete end-to-end security. Here, we introduce a multi-user security framework, offering a general and comprehensive end-to-end key rate formula, against the collaboration of the other network users and eavesdropper. Building on this framework, we propose a multi-user protocol that achieves the theoretical upper limit in all practical deployments within a 100 km range. Applied to a three-node network, it achieves an Mbps-level per-user key rate and an overall network key rate reaching 90\% of the upper limit. The proposed solution supports scalable implementations using telecom-compatible components, while the method for obtaining the accessible information in the network is broadly applicable and can be extended to various multipartite quantum information systems.

quant-ph↗

arXiv2025

Response of Comagnetometer to Exotic Spin-Dependent Couplings

Comagnetometers offer unique advantages in measuring exotic spin-dependent interactions by suppressing magnetic noise. Understanding the frequency response to exotic interactions is essential for evaluating and improving the sensitivity of comagnetometers, as the signals often exhibit distinct spectral features. We conduct theoretical and experimental studies on the frequency response of a differential comagnetometer. We derive analytical expressions for the frequency response of the differential comagnetometer to both magnetic field and exotic couplings, along with the conversion relationship between them. Based on this, we revise the method for determining the axion-nucleon coupling strength with comagnetometers. Furthermore, we introduce a light-shift-based calibration protocol to verify the response to exotic interactions. This work helps predict the sensitivity of comagnetometers in detecting exotic fields and advances the exploration of dark matter.

hep-ph↗

arXiv2025

Thermal Property Microscopy with Compressive Sensing Frequency-Domain Thermoreflectance

Spatial mapping of thermal properties is critical for unveiling the structure-property relation of materials, heterogeneous interfaces, and devices. These property images can also serve as datasets for training artificial intelligence models for material discoveries and optimization. Here we introduce a high-throughput thermal property imaging method called compressive sensing frequency domain thermoreflectance (CS-FDTR), which can robustly profile thermal property distributions with micrometer resolutions while requiring only a random subset of pixels being experimentally measured. The high-resolution thermal property image is reconstructed from the raw down-sampled data through L_1-regularized minimization. The high-throughput imaging capability of CS-FDTR is validated using the following cases: (a) the thermal conductance of a patterned heterogeneous interface, (b) thermal conductivity variations of an annealed pyrolytic graphite sample, and (c) the sharp change in thermal conductivity across a vertical aluminum/graphite interface. With less than half of the pixels being experimentally sampled, the thermal property images measured using CS-FDTR show nice agreements with the ground truth (point-by-point scanning), with a relative deviation below 15%. This work opens the possibility of high-throughput thermal property imaging without sacrificing the data quality, which is critical for materials discovery and screening.

physics.app-ph↗

arXiv2025

Galaxy and halo properties around cosmic filaments from Sloan Digital Sky Survey Data Release 7 and the ELUCID simulation

Using galaxies from the Sloan Digital Sky Survey Data Release 7 (SDSS DR7) along with haloes from the dark matter only constrained ELUCID (Exploring the Local Universe with the reConstructed Initial Density field) simulation, we examine the properties of galaxies and haloes with respect to their distance to cosmic filaments, determined by the medial-axis thinning technique of the COsmic Web Skeleton (COWS) method. Our findings suggest that galaxies or subhaloes grow in mass as they approach these filaments. Galaxies exhibit a redder colour and diminished specific star formation rates as they approach these filaments. Additionally, older subhaloes tend to be more common near the central regions of these filaments. Elliptical galaxies are more frequently found than spiral galaxies in the central regions of the filaments. Lower-mass galaxies typically display reduced sizes in proximity to filaments, whereas higher-mass galaxies tend to exhibit increased sizes when close to filaments. Moreover, the concentration and spin of the haloes grow as they approach the filaments. These findings support the notion that the large-scale structure of the universe, characterized by cosmic web structures, plays a vital role in shaping galaxy and halo properties.

astro-ph.CO↗

arXiv2025

Parameter constraints on a black hole with Minkowski core through quasiperiodic oscillations

We investigate the geodesic motion of charged particles in the vicinity of regular black holes with a Minkowski core, embedded in a uniform magnetic field, and study the influences of magnetic field and regular black hole parameter on the radial effective potential and angular momentum of the particles' orbits. We perturb the circular orbit and analyze the characteristic frequencies of the epicyclic oscillations, which are closely related with the quasiperiodic oscillations (QPOs) phenomena of the accretion disc surrounding the black hole. Then using the MCMC simulation, we fit our theoretical results with four observational QPOs events (GRO J1655-40, XTE J1550-564, XTE J1859+226, and GRS 1915+105) and provide constraints on the magnetic field strength $B$, the characteristic radius $r$, the mass $M$, and the regular black hole parameter $g$. In particular, since the parameter $g$ describes the degree of deviation from the classical Schwarzschild black hole, our studies suggest that, within a certain level of confidence, the black holes in the current model can deviate from the classical singularity structure of Schwarzschild black holes, and exhibit quantum corrections near the core.

gr-qc↗

arXiv2025

The HI Mass Function of the Local Universe: Combining Measurements from HIPASS, ALFALFA and FASHI

We present the first HI mass function (HIMF) measurement for the recent FAST All Sky HI (FASHI) survey and the most complete measurements of HIMF in the local universe thus far. We obtained these results by combining the HI catalogues from HI Parkes All Sky Survey (HIPASS), Arecibo Legacy Fast ALFA (ALFALFA) and FASHI surveys at redshift 0 < z < 0.05, covering 76% of the entire sky. We adopted the same methods to estimate the distances, calculate the sample completeness, and determine the HIMF for all three surveys. The best-fit Schechter function for the total HIMF shows a low-mass slope parameter of alpha = -1.30 and a knee mass log(Ms) = 9.86, along with a normalisation of phi_s = 0.00658. This gives us the cosmic HI abundance: omega_HI= 0.000454. We find that a double Schechter function with the same slope alpha better describes our HIMF, where the two different knee masses are log(Ms1) = 9.96 and log(Ms2) = 9.65. We verify that the measured HIMF is marginally affected by the choice of distance estimates. The effect of cosmic variance is significantly suppressed by combining the three surveys and this provides a unique opportunity to obtain an unbiased estimate of the HIMF in the Local Universe.

astro-ph.GA↗

arXiv2025

ChemicalUniverseMachine I: Uncovering the Cosmic Evolution of Metals in the Galaxy-ISM-CGM Ecosystem

We present an empirical chemical evolution model that explains the distribution of metals in the interstellar medium (ISM) and the circumgalactic medium (CGM) of galaxies based on the UniverseMachine and NeutralUniverseMachine models in the framework of $Λ$CDM structure formation. We parameterize the fractions of outflowing metals returned and mixed into the multi-phase ISM of the star-forming regions ($f_{\rm H2}$) and into the neutral gas regions ($f_{\rm HI}$); metal production, transfer, and dilution are caused by star formation, galaxy mergers, and gas inflow from the inter-galactic medium, respectively, with rates determined by the (Neutral)UniverseMachine models. Using a Markov Chain Monte Carlo algorithm, we explore the posterior distributions of metal return and mixing consistent with observed mass-metallicity relations in HII regions (at $0<z<5$), HI damped Lyman-alpha systems (at $1<z<4$), and the CGM (at $z=0$). We find that the fraction of metals present in the ISM, $f_{\rm H2}+f_{\rm HI}$, increases with halo mass from $\sim20$\% at $10^{10}M_\odot$ to $\sim80$\% at $10^{13}M_\odot$. These fractions increase mildly at higher redshifts, to $\sim30$\% at $10^{10}M_\odot$ and $\sim80$\% at $10^{13}M_\odot$ at $z=5$. Interestingly, there is no significant redshift evolution of $f_{\rm H2}+f_{\rm HI}$ at fixed circular velocity, suggesting that metal distribution between the ISM and CGM is universally determined by the halo potential well depth. CGM metal enrichment is thus slow in high-$z$ halos with deep potential wells. While $f_{\rm H2}$ monotonically increases with halo mass, $f_{\rm HI}$ peaks at $\sim10^{12}-10^{13} M_\odot$, suggesting that reinfall may be inefficient in larger-mass halos.

astro-ph.GA↗

arXiv2025

CSST Large Scale Structure Analysis Pipeline: III. Emission-line Redshift Measurement for Slitless Spectra

The China Space Station Telescope (CSST) is a forthcoming space-based optical telescope designed to co-orbit with the Chinese Space Station. With a planned slitless spectroscopic survey spanning a broad wavelength range of $255-1000$nm and an average spectral resolution exceeding 200, the CSST holds significant potential for cosmic large-scale structure analysis. In this study, we focus on redshift determinations from slitless spectra through emission line analysis within the CSST framework. Our tailored redshift measurement process involves identifying emission lines in one-dimensional slitless spectra, aligning observed wavelengths with their rest-frame counterparts from prominent galaxy emissions, and calculating wavelength shifts to determine redshifts accurately. To validate our redshift measurement algorithm, we leverage simulated spectra generated by the CSST emulator for slitless spectroscopy. The outcomes demonstrate a remarkable redshift completeness exceeding 95 per cent for emission line galaxies (ELGs), alongside a purity surpassing 85 per cent. The redshift uncertainty remains impressively below than $\sim 0.001$. Notably, when concentrating on galaxies with more than three matched emission lines, the completeness of ELGs and the purity of measurable galaxies can reach 98 per cent and 97 per cent, respectively. Furthermore, we explore the influence of parameters like magnitude, spectral signal-to-noise ratio, and redshift on redshift completeness and purity. The discussion also delves into redshift degeneracies stemming from emission-line matching confusion. Our developed redshift measurement process will be applied to extensive simulated datasets and forthcoming CSST slitless spectroscopic observations for further cosmological and extragalactic analyses.

astro-ph.CO↗

arXiv2025

NeutralUniverseMachine: How Filaments and Dark Matter Halo Influence the Galaxy Cold Gas Content

Aims. We aim to investigate the influence of the distance to filaments and dark-matter haloes on galaxy cold-gas content in the empirical model NeutralUniverseMachine (NUM) and the hydrodynamical simulation IllustrisTNG. Methods. We used DisPerSE to identify cosmic web structures and calculate the distance of galaxies to filaments for both observations and models. We show the results of the HI and H2 mass functions, HI- and H2-halo-mass relations, HI- and H2-stellar-mass relations for galaxies in the NUM model and IllustrisTNG with different distances to filaments and compare them with observational measurements. We also show the evolution of HI and H2 mass densities at different distances to filament bins. Results. We find that how filaments affect the HI gas is generally less significant compared to the halo environment. There is a weak trend in the observations at z=0 that low-mass haloes lying closer to the filaments tend to have reduced HI masses. However, this trend reverses for massive haloes with log(Mvir/Msun) > 12.5. This behaviour is accurately reproduced in the NUM model due to the dependence of HI gas on the halo formation time, but it does not appear in IllustrisTNG. The influence of filaments on the HI gas becomes slightly weaker at higher redshifts and is only significant for galaxies that reside in massive haloes in the NUM model. Filaments have almost no impact on the H2-stellar-mass relation in both models, confirming that H2 is primarily determined by the galaxy stellar mass and star formation rate.

astro-ph.GA↗

arXiv2025

The underlying black hole phase transitions in an Einstein-Maxwell-dilaton model with a holographic critical point

The Einstein-Maxwell-dilaton model exhibits a first-order phase transition curve that terminates at a holographic critical endpoint, offering intriguing insights into the phase diagram of the dual system living on the boundary. However, the specific instability within the underlying spacetime that triggers the formation of the hairy black hole remains somewhat obscure. This raises the question of whether one of the hairy black hole phases represents a superconducting or scalarized state and how the two distinct phases merge into a indistinguishable one at the critical point. This work investigates the associated black hole phase transition and the underlying instabilities by exploring a specific Einstein-Maxwell-dilaton model. The approach aims to provide transparent insights into the black hole phase transitions in the bulk. By introducing a nonminimal coupling between a massive real scalar field and a Maxwell field in a five-dimensional anti-de Sitter spacetime, we identify two types of scalarization corresponding to tachyonic instabilities in the ultraviolet and infrared regions. These distinct instabilities lead to a first-order phase transition between two phases in the $μ-T$ phase diagram. Furthermore, this first-order transition terminates at a critical point, beyond which the curve turns back, and the transition becomes a numerically elusive third-order one. Although one does not encounter a critical endpoint, the model still offers a consistent interpretation for the observed {\it cross-over} in the low baryon density region. We analyze the thermodynamic properties of the scalarized hairy black holes and discuss the implications of our findings.

hep-th↗