arXiv subjects

Jinsong Yang

Publications and source records attributed to Jinsong Yang.

At least 19 recordsLinked to original sources

arXiv2026

Quasinormal modes of charged covariant effective black holes with a cosmological constant

In this paper, we investigate the quasinormal modes of two covariant effective black holes characterized by the quantum parameter $ζ$, charge $Q$, and cosmological constant $Λ$, under the scalar perturbation. By employing the pseudo-spectral method, we numerically calculate the quasinormal frequencies and analyze the influence of $ζ$ on the spectra with respect to $Q$. Our results demonstrate that while the quantum parameter $ζ$ significantly modifies the quasinormal frequency spectrum, the non-monotonic behavior and overtone outbursts persist. Notably, the impact of quantum gravity on the overtone outbursts is not merely limited to enhancement or suppression; instead, it introduces additional spectral features. Furthermore, a comprehensive analysis of the full quasinormal mode spectrum reveals rich interactions between complex and purely imaginary modes, including damping-rate crossings and merging-splitting behavior. These phenomena typically accompany overtone outbursts in near-extremal regimes, suggesting a potential connection between mode interactions and overtone outbursts. This work emphasizes the necessity of analyzing the full quasinormal frequency spectrum rather than focussing solely on fundamental modes, and provides novel insights into its underlying spectral structures.

gr-qc↗

arXiv2026

Gravitational waveforms and accretion characteristics in a quantum-corrected black hole without Cauchy horizons

The use of physical phenomena in the strong-field regime has become a primarily methodology for probing quantum-corrected gravity. This paper investigates periodic orbits, gravitational waves, and accretion disk radiation for a quantum-corrected black hole without Cauchy horizons. First, by analyzing the trajectory equations of massive particles in the equatorial plane, we study the influence of the quantum parameter $ζ$ on the stability of circular orbits. The results show that an increase in $ζ$ leads to an outward migration of both the innermost stable circular orbit and the marginally bound orbit, accompanied by an increase in the required specific angular momentum for particle motion on these two orbits. Then, we further investigate the periodic orbit characteristics of particles and compute the associated gravitational waveforms for extreme mass-ratio inspirals. It is demonstrated that quantum corrections induce a cumulative phase shift in the gravitational wave signal, leading to significant dephasing compared to the classical Schwarzschild case. Furthermore, based on the Novikov-Thorne thin accretion disk model, we evaluate the radiation characteristics of the accretion disk around this quantum-corrected black hole. The results indicate that the introduction of the quantum parameter suppresses the radiant energy flux, effective temperature, and overall radiative efficiency of the disk. These distinctive dynamical and radiative deviations provide potential phenomenological support for distinguishing quantum-corrected geometries from classical black holes using multiple observational means in the future.

gr-qc↗

arXiv2026

Black holes and covariance in effective quantum gravity: A solution without Cauchy horizons

The issue of general covariance in effective quantum gravity models within the Hamiltonian framework is addressed. The previously proposed equations for the covariance condition in spherically symmetric models are explicitly derived. By solving this equation, a new effective Hamiltonian constraint is obtained, incorporating free functions that can account for quantum gravity effects. The resulting spacetime structure is analyzed by specifying the free functions. Remarkably, in this model, the classical singularity is replaced by a region where the metric asymptotically approaches a Schwarzschild-de Sitter one with negative mass. Thus, this new quantum-corrected black hole model avoids the Cauchy horizons presented typically in previously studied models. The covariant approach is also applicable to matter coupling in the models.

gr-qc↗

arXiv2026

Black Holes and Covariance in Effective Quantum Gravity

The longstanding issue of general covariance in effective models of quantum gravity is addressed, which arises when canonical quantum gravity leads to a semiclassical model described by an effective Hamiltonian constraint. In the context of spherically symmetric models, general covariance is precisely formulated into a set of equations, leading to the necessary and sufficient conditions for ensuring covariance. With the aid of these conditions, we derive the equations for the effective Hamiltonian constraint. The equations yield two candidates for effective Hamiltonian constraints dependent on a quantum parameter. The resulting quantum modified black hole spacetimes are analyzed. Our models show improvement by casting off the known limitations of previous works with similar results.

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arXiv2026

FinSight-Net:A Physics-Aware Decoupled Network with Frequency-Domain Compensation for Underwater Fish Detection in Smart Aquaculture

Underwater fish detection (UFD) is a core capability for smart aquaculture and marine ecological monitoring. While recent detectors improve accuracy by stacking feature extractors or introducing heavy attention modules, they often incur substantial computational overhead and, more importantly, neglect the physics that fundamentally limits UFD: wavelength-dependent absorption and turbidity-induced scattering significantly degrade contrast, blur fine structures, and introduce backscattering noise, leading to unreliable localization and recognition. To address these challenges, we propose FinSight-Net, an efficient and physics-aware detection framework tailored for complex aquaculture environments. FinSight-Net introduces a Multi-Scale Decoupled Dual-Stream Processing (MS-DDSP) bottleneck that explicitly targets frequency-specific information loss via heterogeneous convolutional branches, suppressing backscattering artifacts while compensating distorted biological cues through scale-aware and channel-weighted pathways. We further design an Efficient Path Aggregation FPN (EPA-FPN) as a detail-filling mechanism: it restores high-frequency spatial information typically attenuated in deep layers by establishing long-range skip connections and pruning redundant fusion routes, enabling robust detection of non-rigid fish targets under severe blur and turbidity. Extensive experiments on DeepFish, AquaFishSet, and our challenging UW-BlurredFish benchmark demonstrate that FinSight-Net achieves state-of-the-art performance. In particular, on UW-BlurredFish, FinSight-Net reaches 92.8% mAP, outperforming YOLOv11s by 4.8% while reducing parameters by 29.0%, providing a strong and lightweight solution for real-time automated monitoring in smart aquaculture.

cs.CV↗

arXiv2026

Optical appearance of Schwarzschild black holes with optically thin and thick accretion disks at various inclination angles

In this paper, we systematically investigate the optical appearance of a Schwarzschild black hole illuminated by three geometrically thin accretion disk models under varying observational inclination angles. Based on the geometric relationship between the black hole and observer, we first divide the accretion disk into co-side and counter-side semi-disks. We then analyze light ray trajectories, and calculate the total number of orbits and transfer functions for both semi-disks. The results reveal distinct inclination-dependence of lensed regions on different semi-disks: as inclination increases, the lensed region contracts for the counter-side semi-disk while expanding for the co-side one. Furthermore, through explicit specification of the emission profiles of the three models, we present optical images for both optically thin and thick disk scenarios at different inclinations. The results demonstrate that: (i) the bright rings in all three models become progressively compressed and deviate from circularity as inclination increases; (ii) for thick disks, partial rings are obscured and the overall intensity is lower than thin disks. These results may advance our understanding of general black hole imaging processes and provide a new approach to test gravitational theories through optical morphology studies.

gr-qc↗

arXiv2026

Electric Penrose process in the spacetime of a quantum-corrected Reissner-Nordstr\"om black hole

In this paper, we study the electric Penrose process for charged particles in the spacetime of a covariant quantum-corrected Reissner-Nordstr\"om black hole. We first derive the equations of motion for charged particles around the black hole, and then analyze how the quantum parameter $\zeta$ modifies the generalized ergoregion boundary and affects the energy-extraction efficiency. We further analyze the subsequent motion of charged particles in the electric Penrose process, and rigorously prove that under specific simplified conditions, the resulting fragment particle can always escape to a distant observer with a net energy gain, a conclusion applicable to a wide range of charged black hole models. Finally, we study the electric Penrose process in a critical regime where the initial particle is bound, yet its high-energy fragment particle may still escape. A key finding is that while $\zeta$ slightly alters the particle trajectories, it can qualitatively alter outcomes near critical conditions, causing a fragment particle that would escape in the classical black hole spacetime to become trapped in the quantum-corrected one. These results collectively demonstrate the obstructive effect of quantum corrections on the Penrose process and provide potential kinematic signatures to distinguish the quantum-corrected from classical Reissner-Nordstr\"om black holes.

gr-qc↗

arXiv2025

Black hole images as probes of thermodynamic evolution

Observable signatures of black hole thermodynamics remain far from fully explored. Previous works have suggested that thermodynamic phase transitions of black holes could leave imprints on their images. In this work, we demonstrate that richer black hole thermodynamic information can also leave imprints on the resulting images. Using the charged anti-de Sitter black hole as an example, we study the evolution of its images (shadow and accretion-disk images) along isobaric and isothermal processes. We find that the image size evolves monotonically along isobars but becomes nonmonotonic along isotherms. After further considering phase transitions, the image size exhibits a sudden increase in both thermodynamic processes. More importantly, in the isothermal process, the phase transition further results in the emergence of a critical reduced temperature that separates two qualitatively distinct image evolutions. These results show that black hole images can probe not only phase transitions, but also thermodynamic process and temperature.

gr-qc↗

arXiv2025

Revisiting particle circular orbits as probes of black hole phase transitions

Previous studies suggested that the particle circular orbit can serve as a probe of black hole phase transitions. However, these studies only identified this phenomenon by substituting the horizon radius $r_h$ with the circular orbit radius $r_c$ in thermodynamic state relations. Such simplistic substitution fails to uncover the underlying connection between black hole phase transitions and particle circular orbits. In this work, we successfully establish this profound intrinsic link by deriving a differential relation for $r_c$ that relates to thermodynamic parameters and the first law of black hole thermodynamics. Using this relation, we demonstrate that during a first-order phase transition, if $r_h$ experiences a discontinuous jump (such as in the small/large black hole phase transition), then $r_c$ must simultaneously undergo a discontinuous jump. This finding confirms that particle circular orbits can indeed serve as probes of first-order phase transitions. More importantly, we show that this phenomenon is a direct consequence of the nonzero latent heat inherent to first-order phase transitions. Finally, we demonstrate that the jump sizes $\Delta r_c$ and $\Delta r_h$ across the phase transition share the same critical exponent at the thermodynamic critical point, indicating that $\Delta r_c$ can serve as an order parameter for black hole phase transitions. Notably, this conclusion follows directly from the first law.

gr-qc↗

arXiv2025

Image of a quantum-corrected black hole without Cauchy horizons illuminated by a static thin accretion disk

Latest advances in effective quantum gravity propose a quantum-corrected black hole solution that avoids Cauchy horizons. This paper studies the images of this black hole when illuminated by a static thin accretion disk and explores the effect of the quantum parameter {\zeta} on its appearance. First, we investigate the influence of {\zeta} on the event horizon, photon sphere, critical impact parameter, and innermost stable circular orbit associated with the black hole. We find that all these quantities exhibit an increase with increasing {\zeta}. Meanwhile, we also use observational data from M87* and Sgr A* to impose constraints on {\zeta} and compare the results with the theoretical constraint. Our analysis reveals that the observational constraint from Sgr A* is stronger than the theoretical one. We then derive the photon trajectory equation and analyze briefly the behavior of the trajectories. A detailed analysis shows that as {\zeta} increases, the trajectories of photons undergo slight modifications when approaching the event horizon. Finally, by plotting the black hole's optical appearance under three emission models, we find that as {\zeta} increases, the quantum-corrected black hole exhibits a larger shadow, along with narrower lensed and photon rings and reduced spacing between them. Furthermore, we also implement Johnson's unbound distribution to simulate the image of the quantum-corrected black hole under large quantum parameters and reach the same conclusion. This work validates the rationality of this black hole solution through observational data, and provides its unique optical signatures that can serve as a promising avenue for probing quantum gravity effects near black holes.

gr-qc↗

arXiv2025

Covariant effective spacetimes of spherically symmetric electrovacuum with a cosmological constant

An algebraic framework was introduced in our previous works to address the covariance issue in spherically symmetric effective quantum gravity. This paper extends the framework to the electrovacuum case with a cosmological constant. After analyzing the notion of covariance in the classical theory, we propose an effective Hamiltonian for the electromagnetic field. The effective Hamiltonian together with the effective Hamiltonian constraint of gravity determines an effective dynamical model of gravity coupled to the electromagnetic field. The resulting model is covariant with respect to both the effective metric and the effective vector potential. By solving the equations of motion derived from the effective Hamiltonian constraint, we obtain several quantum-corrected solutions. Notably, some of these solutions reveal quantum gravity effects manifesting not only in spacetime metrics but also in the electromagnetic field. Finally, the covariance of coupling models with general matter fields is discussed.

gr-qc↗

arXiv2025

Motion of spinning particles around a quantum-corrected black hole without Cauchy horizons

In this paper, we investigate the motion of spinning particles around a covariant quantum-corrected black hole without a Cauchy horizon within the framework of effective quantum gravity, and examine the influence of quantum gravitational effects on the motion of these spinning particles. First, we employ the Mathisson-Papapetrou-Dixon equations to derive the 4-momentum and 4-velocity of spinning particles, and introduce the effective potential for radial motion using the components of the 4-momentum. We find that an increase in the quantum parameter $ζ$ leads to a decrease in the effective potential, while the spin $S$ significantly affects the magnitude of the effective potential. Then, through the effective potential, we investigate the properties of circular orbits and the innermost stable circular orbit, and discuss the timelike condition that spinning particles must satisfy when moving around the black hole. Finally, we study the trajectories of spinning particles on bound orbits around the quantum-corrected black hole and compare them with those around other covariant quantum-corrected black holes. The results show that the trajectories of spinning particles in this quantum-corrected black hole model are weakly influenced by $ζ$, making them almost indistinguishable from those in the Schwarzschild black hole, but they can be distinguished from other covariant quantum-corrected models under certain initial conditions. These results contribute to our understanding of black hole properties under quantum corrections.

gr-qc↗

arXiv2025

EPANet: Efficient Path Aggregation Network for Underwater Fish Detection

Underwater fish detection (UFD) remains a challenging task in computer vision due to low object resolution, significant background interference, and high visual similarity between targets and surroundings. Existing approaches primarily focus on local feature enhancement or incorporate complex attention mechanisms to highlight small objects, often at the cost of increased model complexity and reduced efficiency. To address these limitations, we propose an efficient path aggregation network (EPANet), which leverages complementary feature integration to achieve accurate and lightweight UFD. EPANet consists of two key components: an efficient path aggregation feature pyramid network (EPA-FPN) and a multi-scale diverse-division short path bottleneck (MS-DDSP bottleneck). The EPA-FPN introduces long-range skip connections across disparate scales to improve semantic-spatial complementarity, while cross-layer fusion paths are adopted to enhance feature integration efficiency. The MS-DDSP bottleneck extends the conventional bottleneck structure by introducing finer-grained feature division and diverse convolutional operations, thereby increasing local feature diversity and representation capacity. Extensive experiments on benchmark UFD datasets demonstrate that EPANet outperforms state-of-the-art methods in terms of detection accuracy and inference speed, while maintaining comparable or even lower parameter complexity.

cs.CV↗

arXiv2025

Periodic orbits and gravitational waveforms in quantum-corrected black hole spacetimes

In this paper, we study the periodic orbits of massive particles around two quantum-corrected black holes proposed in effective quantum gravity, and explore the quantum gravity effect on both the particle orbits and the associated gravitational wave signals. First, we analyze the geodesic motion of the massive particle around the black holes. We then study two important types of bound orbits of the massive particles, the marginally bound orbit and the innermost stable circular orbit. We find that, for the first black hole, increasing the quantum parameter $ζ$ leads to larger orbital radii and reduced angular momenta for both orbits. In contrast, the second black hole shows $ζ$-independent orbital radii and angular momenta. By analyzing the effective potential, we determine the allowed range of the energy and the angular momentum for bound orbits, with $ζ$-dependence only for the first black hole. We further investigate periodic orbits with a fixed energy for both black holes, revealing that the parameter $ζ$ similarly affects the orbits, although its effect is negligible in the second black hole. Finally, we calculate the gravitational waves emitted by the periodic orbits. The results demonstrate that increasing $ζ$ leads to a significant phase delay for the first black hole, while only inducing a subtle phase advance for the second one. Therefore, we conclude that the first black hole can be distinguished from the Schwarzschild one through gravitational wave observations, whereas the second one cannot be effectively distinguished when the quantum correction is weak.

gr-qc↗

arXiv2025

Shadows and optical appearance of quantum-corrected black holes illuminated by static thin accretions

Recently, two new quantum-corrected black hole models satisfying covariance have been proposed within the framework of effective quantum gravity. In this paper, we study how the quantum parameter $ζ$ affects the optical properties of two quantum-corrected black hole models. We first analyze the photon sphere, critical impact parameter, and innermost stable circular orbit as $ζ$ varies, and constrain $ζ$ using Event Horizon Telescope data. Additionally, by employing the ray-tracing method to study photon trajectories near the two quantum-corrected black holes, we find that $ζ$ can reduce the range of impact parameters corresponding to the photon ring and lensed ring. We then examine the optical appearance of these black holes with thin accretion disks, showing $ζ$ significantly brightens the first model's image but has little effect on the second. Meanwhile, we demonstrate the contributions of the transfer functions to the observed intensity of direct and lensed ring in the observer's field of view, which has rarely been separately illustrated in previous studies. Finally, we study the optical appearance of both quantum-corrected black holes under a static spherical accretion model, with results consistent with the above. Therefore, we conclude that the second quantum-corrected black hole is almost indistinguishable from the Schwarzschild black hole, while the first quantum-corrected black hole can be distinguished from the Schwarzschild black hole through its optical appearance.

gr-qc↗

arXiv2025

Self-evolving Agents with reflective and memory-augmented abilities

Large language models (LLMs) have made significant advances in the field of natural language processing, but they still face challenges such as continuous decision-making. In this research, we propose a novel framework by integrating iterative feedback, reflective mechanisms, and a memory optimization mechanism based on the Ebbinghaus forgetting curve, it significantly enhances the agents' capabilities in handling multi-tasking and long-span information.

cs.CL↗

arXiv2025

Investigating shadow of a rotating charged black hole with a cosmological constant immersed in the perfect fluid dark matter

In this paper, we mainly investigate the shadow of a rotating charged black hole with a cosmological constant immersed in perfect fluid dark matter. We first obtain the charged spherically symmetric black hole with a cosmological constant solution immersed in perfect fluid dark matter by using the gravitational decoupling method. Based on the mass function seed source of the spherically symmetric solution, we construct a rotating charged black hole with a cosmological constant immersed in perfect fluid dark matter, and study the effects of the perfect fluid dark matter parameter $α$, cosmological constant $Λ$, electric charge $Q$, and rotating parameter $a$ on the event horizons of the rotating black hole. We then derive the geodesic equation of photon of the rotating charged black hole with a cosmological constant immersed in perfect fluid dark matter. In addition, we analyze the influences of the four black hole parameters on the effective potential functions of photon, the boundaries, and the deformations of the rotating black hole shadows. Particularly, we find that the effects of the $α$ on the event horizons, the effective potential functions, the boundaries, and the deformations of the black hole shadows are more obvious than the other three parameters ($Λ, Q$, and $a$). We expect our results will be useful in the future to relate the theoretical models of perfect fluid dark matter and dark energy with observations of celestial bodies immersed in dark matter and dark energy.

gr-qc↗

arXiv2024

Shadows of rotating black holes in effective quantum gravity

Recently, two new spherically symmetric black hole models with covariance have been proposed in effective quantum gravity. Based on these models, we use the modified Newman-Janis algorithm to generate two rotating quantum-corrected black hole solutions, characterized by three parameters, the mass $M$, the spin $a$, and the quantum parameter $ζ$. To understand the effects of the quantum parameter $ζ$ on these two rotating black holes, we investigate in detail the horizons and static limit surfaces. By constraining the possible range of the parameters, we study the shadows cast by these rotating black holes. The results indicate that for both rotating BHs, the parameter $ζ$ mainly affects the shadow size in the non-extremal case, while it deforms the shadow shape by arising a cuspy edge in the near-extremal case.

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