arXiv subjects

Yao-Guang Zheng

Publications and source records attributed to Yao-Guang Zheng.

At least 19 recordsLinked to original sources

arXiv2026

Thermodynamic Regulation of Superradiance in a Charged Two-Dimensional Black Hole

Within the framework of gravitational thermodynamicization, we investigate the propagation of charged scalar fields in static two-dimensional black-hole spacetimes. Starting from the scalar-field action, we derive the exact radial wave equation and show that a neutral, massless, minimally coupled scalar field in a genuinely two-dimensional geometry exhibits neither an angular-momentum barrier nor superradiant amplification. For a charged scalar field, the condition for amplification is governed by the electrostatic potential evaluated at the event horizon. In the case of the charged two-dimensional string black hole, the horizon electrostatic potential is directly related to the Hawking temperature, implying that the superradiant frequency window is determined by the thermodynamic state of the black hole. We further formulate a near-horizon residue criterion that provides a coordinate-independent characterization of the superradiant threshold. When a reflecting outer boundary is imposed, necessary frequency conditions for unstable modes are derived, together with an upper bound on their growth rates. Numerical calculations verify the corresponding flux relation and clearly distinguish superradiant scattering from genuine superradiant instability.

physics.gen-ph↗

arXiv2025

THE KERR-SEN Solution Satisfying SO(2) Symmetry

We present a new class of KERR-SEN solutions that respect SO(2) symmetry, constructed systematically using the Laurent series expansion method. This approach is based on stationary, axisymmetric Euclidean solutions to the vacuum Einstein equations and incorporates advanced techniques for generating stationary gravitational fields, including the variation-of-constants method and nonlinear superposition. Through this unified framework, we obtain fresh insights into axially symmetric gravitational systems, extend the traditional hierarchy of Kerr-NUT solutions, and bring together several foundational analytic methods under a common structure. The paper offers explicit derivations, supported by numerical simulations, and provides a detailed discussion of the physical consequences, particularly focusing on the roles of dilaton and axion fields. The extended version also includes a comprehensive historical overview of axisymmetric exact solutions, a thorough explanation of the Laurent series formalism in gravitational theory, and an in-depth analysis of the theoretical and astrophysical significance of KERR-SEN metrics in current research.

gr-qc↗

arXiv2025

Extending the short gamma-ray burst population from sub-threshold triggers in Fermi/GBM and GECAM data and its implications

Detection of short gamma-ray bursts (SGRBs) is critically important for the research of compact object mergers and multi-messenger astrophysics, but a significant part of SGRBs fall below the trigger threshold of GRB detectors, and thus are often missed. Here we present a systematic search for and verification of missed SGRBs using Fermi/GBM subthreshold triggers, jointly analyzing data from GBM, GECAM-B, and GECAM-C. Among 466 Fermi/GBM sub-threshold events (with reliability >= 5) from 2021 to 2024, 181 are within GECAM's field of view. We find that 49 out of 181 are confirmed astrophysical transients, and 41 can be classified as SGRBs. Thus, the SGRB detection rate of Fermi/GBM is increased to about 50 per year. Additionally, a complete multi-instrument monitoring and systematic verification of GBM sub-threshold events is expected to further increase the SGRB rate to about 80 per year, which is about 100% improvement relative to the GBM-triggered SGRBs. These results may have important implications on the local formation rate of SGRBs and the binary neutron star merger rate. We also searched for potential temporal coincidences between these SGRBs and gravitational waves from the LIGO-Virgo-KAGRA O4 run resulting in no detection.

astro-ph.HE↗

arXiv2025

Advanced Analysis of Hawking Temperature Calculation for Novel Topological Black Holes using Laurent Series and the RVB Method

This paper employs Laurent series expansions and the Robson--Villari--Biancalana (RVB) method to provide a refined derivation of the Hawking temperature for two newly introduced topological black hole solutions. Previous calculations have demonstrated inconsistencies when applying traditional methods to such exotic horizons, prompting the need for a more thorough mathematical analysis. By systematically incorporating higher-order terms in the Laurent expansions of the metric functions near the horizon and leveraging the topological features characterized by the Euler characteristic, we reveal additional corrections to the Hawking temperature beyond standard approaches. These findings underscore the subtle interplay between local geometry, spacetime topology, and quantum effects. The results clarify discrepancies found in earlier works, present a more accurate representation of thermodynamic properties for the black holes in question, and suggest broader implications for topological structures in advanced gravitational theories.

gr-qc↗

arXiv2024

Verification of the First Law of Horizon Thermodynamics for Schwarzschild, Reissner-Nordström, Kerr, and Kerr-Newman Black Holes in Four-Dimensional f(R) Gravity with Dual Scalar Fields

This paper demonstrates the validity of the first law of horizon thermodynamics for Schwarzschild, RN, Kerr, and Kerr-Newman (KN) black holes within the framework of four-dimensional f(R) gravity coupled with dual scalar fields. Starting from a five-dimensional membrane world scenario, we derive the four-dimensional effective f(R) gravity action and obtain the corresponding black hole solutions. We then verify that these solutions satisfy the first law of black hole thermodynamics by explicitly calculating the variations of thermodynamic quantities. The analysis confirms the robustness of the horizon thermodynamics framework in extended gravitational theories, providing insights into the interplay between higher-dimensional theories and four-dimensional black hole thermodynamics.

gr-qc↗

arXiv2024

Thermodynamic geometric analysis of 3D charged black holes under f(R) gravity

This article investigates 3D charged black holes within the scope of f(R) gravity, focusing on their thermodynamic attributes. The research primarily examines minor fluctuations around these black holes' equilibrium states and delves into their modified thermodynamic entropy. Utilizing geometric thermodynamics (GTD), the study evaluates the curvature scalar's role in pinpointing phase transition points in these black holes. A key finding is that several 3D charged black holes under f(R) gravity display thermodynamic properties akin to an ideal gas when their initial curvature scalar remains constant. Conversely, with a non-constant curvature scalar and a cosmological constant term that includes a negative exponent, these black holes exhibit characteristics similar to a van der Waals gas. The article outlines general solutions for scenarios involving non-negative powers and specific solutions for cases with negative powers. Notably, under certain conditions, a phase transition resembling that of a van der Waals gas is observed, suggesting a strong correlation between the black hole's fate and the cosmological constant, extending beyond the parameters proposed by the no-hair theorem.The research provides insights into the swift decline of peaks linked to both large and small black holes, revealing new aspects of black hole transitional behaviors. In a three-dimensional space (for $d=3$) with a variable $k_1$ set to 1, and considering a $Λ$ term that adheres to SO(2) symmetry, the study uncovers a cusp catastrophe in the G-T function graph. This observation, within the specified metric, points to a distinct solution that characterizes the ``Phase Transition and Properties of Bose-Einstein Condensation" under specific conditions. Notably, this phase transition in Bose-Einstein condensation occurs due to the symmetry shift from SO(3) to SO(2).

physics.gen-ph↗

arXiv2024

Thermodynamic Properties of Modified Black Hole Metrics in $f(R)$ Gravity

To construct new Schwarzschild and Kerr-Newman metric solutions, we start from the Lagrangian in entropy and statistical mechanics, introducing $f(R)$ gravity theory and dark energy definitions. Through a series of calculations, we derive the corrected metric solutions under different forms of $f(R)$ gravity.

physics.gen-ph↗

arXiv2024

Thermodynamic geometric analysis of RN black holes under f(R) gravity

In this article, we explore the RN black hole under f(R) gravity and its thermodynamic properties. We begin by examining the small fluctuations around the equilibrium state and summarizing the expression for the modified thermodynamic entropy of this black hole. Additionally, we delve into the geometric thermodynamics (GTD) of black holes and investigate the suitability of the curvature scalar of the GTD method for the phase transition point of the black hole. Moreover, we investigate the effects of modified parameters on the thermodynamic behavior of black holes.Within the framework of $f(R)$ modified gravity theory, we discovered that several RN black holes demonstrate thermodynamic properties resembling those of an ideal gas when the initial curvature scalar of the black hole remains constant. However, if the initial curvature scalar is non-constant and the cosmological constant term possesses a negative exponent, the Reissner-Nordström (RN) black holes could exhibit characteristics akin to those of a van der Waals gas.We separately list the general solutions for the case of non-negative powers and the special solutions for the case of negative powers. We observe that, under certain conditions, the phase transition analogous to the Van der Waals gas exists for charged black holes under f(R) gravity.

physics.gen-ph↗

arXiv2023

Refined Perspectives on the Kerr-Schild Double Copy:Harmonizing Gravity and Electromagnetism in Metric Formulations

This paper explores the Kerr-Schild double copy, a duality relating gravity and electromagnetism. We show how Einstein's vacuum solutions in four dimensions can be converted into Maxwell's solutions via a double copy procedure, employing tensor fields. This technique yields novel solutions to Einstein's equations, including Kerr, Schwarzschild, and RN black holes. Introduced by Kerr and Schild in 1965, the Kerr-Schild action decouples the gravitational and matter fields, surpassing the Einstein-Hilbert action in facilitating calculations. It holds significant value for studying gravitational waves, cosmology, and black hole thermodynamics. We further delve into the applications of the Kerr-Schild double copy in deriving black hole solutions, analyzing gravitational waves, exploring alternative cosmological theories, and understanding black hole thermodynamics. Moreover, we investigate the implications of this double copy under SO(3) and SU(2) symmetries on the Schwarzschild and Kerr-Newman black hole metrics.

gr-qc↗

arXiv2023

The Quantum and thermodynamic properties of dyonic RN-like black holes

The effect of magnetic fields on black hole superradiance is an exciting topic with possible astrophysical applications. A dyonic RN-like black hole is not asymptotically flat. It describes a black hole immersed in an asymptotically uniform magnetic field. This paper discusses the superadditive stability of binary RN black holes, asymptotically flat, band-like black holes. This article introduces the above condition into dyonic RN-like black holes if a dyonic RN-like black hole satisfies the requirement of $μ=yω$, When $\sqrt{2(B^2+Q^2)}/{r^2_+}< ω< q\varPhi_H$,particularly $μ\ge \sqrt{2}(q\varPhi_H)$,the dyonic RN-like black hole is superradiantly stable at that time.Scalars can be seen as combinations of positive/negative powers of a base, much like the decimal system. This principle is key in math and computing, from number systems to Fourier series (linked to $e^{i x}$ ). Dyonic RN-like black holes show no phase transition.

physics.gen-ph↗

arXiv2023

The possibility of the no-hair theorem being violated

Recently, one of my articles presented intriguing findings on the superradiant stability of Kerr black holes. These findings drew conclusions that appear to challenge the established ``No Hair Theorem". As is widely known, the ``No Hair Theorem" stems from the principles of general relativity. In this paper, we thoroughly examine the nexus between Bell's theorem and the uncertainty principle. By delving deep into the theoretical underpinnings of both concepts, we illustrate that Bell's theorem occupies a more foundational stance within the landscape of uncertainty. This gives rise to a particular probability, shedding light on why the no-hair theorem might not hold in the face of quantum effects. It's possible that while the no-hair theorem remains valid, the combined effects of classical and quantum mechanics introduce additional variations to the three parameters of the black hole. This nuance could represent a modest advancement in cosmological research.

physics.gen-ph↗

arXiv2023

Fermions can also produce super-radiation phenomena

According to traditional theory, it is believed that Fermions do not exhibit superradiation. However, when predetermined boundary conditions are in place, there is a possibility of combining the wave function of coupled Fermions, which can result in the emergence of superradiation phenomena. This article presents a novel perspective, proposing that Fermions have the potential to display superradiation phenomena. This implies that there is a broader scope for investigating superradiation and its relationship with boundary conditions.

physics.gen-ph↗

arXiv2023

Calculating the Hawking Temperatures of Kerr-Newman Black Holes in the f(R) Gravity Models with the RVB Method

In this study, we conducted a comparison between the RVB method and the conventional method discussed in previous literature for calculating the Hawking temperature of Kerr-Newman black holes under f(R) gravity\cite{9,10,11}. Our research findings are in agreement with the results presented in the literature\cite{17}, with only a variation in the integration constant. Through the comparison of these two methods, we arrived at consistent conclusions.After conducting a thorough comparison between the RVB method and the temperature Green's function method, we have found that these two approaches are fundamentally identical. This significant finding highlights the high level of consistency between the temperature Green's function method and the RVB method.

physics.gen-ph↗

arXiv2023

Schwarzschild black hole can also produce super-radiation phenomena under f(R) Gravity and the cosmic censorship conjecture may be violated

This article suggests that Bose-Einstein condensation can occur without the need for an energy barrier when the boundary conditions are set as $\frac{T}{T_{c}}=z$ (where z is a positive integer). Under these conditions, bosons can condense in the Schwarzschild black hole. The incident waves can then be trapped and condensed within the black hole, generating a potential barrier near the event horizon. This suggests that Schwarzschild black holes under f(R) Gravity can also exhibit superradiance, which raises the possibility of violating the cosmic censorship conjecture. It should be noted that the natural unit system is used in this article.

physics.gen-ph↗

arXiv2023

Wormhole Stability of Charged Black Holes Under the Gravity of f(R)

In this paper, we propose that since Hawking radiation may be a kind of superradiation, the action of superradiation with preset bounds satisfies some higher-dimensional action structure, e.g., bosons in the preset springs of Kerr black hole. The superradiation meets the algebraic system of bosons on Kerr-Schild black holes. We think that the superradiation of bounded fermions to Kerr structure black holes benefits the mapping structure of wormholes. By analogy, we find the entropy algebraic expression of the wormhole in the charged black hole under f(R) gravity and then conduct thermodynamic geometric analysis to find out the stability condition of the wormhole.

physics.gen-ph↗

arXiv2022

The superradiant stability of Kerr-Newman black holes

In this article, the superradiation stability of Kerr-Newman black holes is discussed by introducing the condition used in Kerr black holes y into them. Moreover, the motion equation of the minimal coupled scalar perturbation in a Kerr-Newman black hole is divided into angular and radial parts. Hod proved\cite{12} that the Kerr black hole should be superradiantly stable under massive scalar perturbation when $μ\ge \sqrt{2}mΩ_H$, where $μ$ is the mass. In this article, a new variable y is added here to expand the results of the above article. When $\sqrt{2(a^2+Q^2)}/{r^2_+}< ω< m\varOmega_H+q\varPhi_H$,particularly $μ\ge \sqrt{2}(m\varOmega_H+q\varPhi_H)$,so the Kerr-Newman black hole is superradiantly stable at that time.

gr-qc↗

arXiv2022

Thermodynamic geometry analysis of new Schwarzschild black holes

This article puts forward a hypothesis.In this article, the derivative of the cosmological constant is positive, and there is a possibility that the constant evolves from negative in the early universe to positive in the later period. We see that when the black hole is an extreme black hole $r_{+}=r_{-}$, the curvature scalar vanishes to zero. In general, the curvature scalar is not equal to zero. When $r_{+}=3 r_{-}$, the curvature scalar is equal to negative infinity. According to Ruppeiner's theory, this time represents the phase transition of the system. It is very interesting that the divergence point of the curvature scalar happens to be the Davis transition point. We have found the phase transition point of the new Schwarzschild black hole.

gr-qc↗

arXiv2022

The First Insight-HXMT Gamma-Ray Burst Catalog: The First Four Years

The Hard X-ray Modulation Telescope (Insight-HXMT), is China's first X-ray astronomy satellite launched on June 15, 2017. The anti-coincidence CsI detectors of the High Energy X-ray telescope (HE) onboard Insight-HXMT could serve as an all-sky gamma-ray monitor in about 0.2-3 MeV. In its first four years of operation, Insight-HXMT has detected 322 Gamma-Ray Bursts (GRBs) by offline search pipeline including blind search and targeted search. For the GOLDEN sample of Insight-HXMT GRBs, joint analyses were performed with other GRB missions, including Fermi Gamma-ray Burst Monitor (Fermi/GBM), Swift Burst Alert Telescope (Swift/BAT) and Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM). It shows that Insight-HXMT can provide better constraint on GRB spectrum at higher energy band. The properties of Insight-HXMT GRBs are reported in detail, including their trigger time, duration, spectral parameters, peak fluxes of different time scales and fluence. This catalog is an official product of the Insight-HXMT GRB team.

astro-ph.HE↗