arXiv subjects

Yu-Sen An

Publications and source records attributed to Yu-Sen An.

At least 19 recordsLinked to original sources

arXiv2026

Chaotic Imprints in Gravitational Waves from Conformal-Anomaly-Corrected Extreme-Mass-Ratio Inspirals

In this work, we investigate the effect of chaotic orbits on the extreme mass ratio inspiral (EMRI) gravitational wave signals where the central black hole is corrected by quantum conformal anomaly. We utilize the numerical kludge method to compute gravitational waveforms produced by the compact object along different orbital trajectories, and also derive the corresponding frequency distribution and energy spectra of gravitational waves. Our calculations reveal that variations in orbital energy or anomaly coefficient drive the orbital evolution from regular integrable motion to chaotic motion, and such dynamical transition leaves clear imprints on gravitational-wave signal. Specifically, gravitational waves originating from chaotic orbits feature pronounced irregular and time-varying amplitude fluctuations, accompanied by abundant fine spectral spikes and extended continuous spectral distributions in both frequency and energy domains, which differ drastically from the gravitational radiation generated by the regular non-chaotic orbits. Moreover, we evaluate the detectability by comparing the calculated characteristic strain of gravitational waves emitted by the compact object on different orbits with the sensitivity curves of future space-based GW detectors, including LISA, Taiji and TianQin. The results demonstrate that these detectors are capable of capturing gravitational-wave signals from chaotic systems modified by conformal anomalies, which provide a potential pathway for detecting conformal anomaly correction in astronomical observation.

gr-qc↗

arXiv2026

Chaotic particle dynamics near a traversable wormhole throat

This study investigates the nonlinear dynamics of a test particle near the traversable wormhole throat under an external harmonic potential. One-dimensional radial perturbation analysis shows that the particle is locally linearly stable at the equilibrium position. However, for two-dimensional and high-energy cases, the system exhibits a nonlinear response, leading to large-scale chaos. The analysis indicates that, if the particle is confined on one side of the wormhole, the Poincare section will still retain Kolmogorov-Arnold-Moser (KAM) tori under extremely high-energy conditions, which is distinct from the chaos caused by the event horizon in the black hole. By studying another set of shape functions, the universality of this phase space structure is confirmed. This research clarifies the unique nonlinear dynamical mechanism of a traversable wormhole. It provides a new criterion, based on chaotic dynamics, for identifying black hole mimickers in strong-field astrophysical observations.

gr-qc↗

arXiv2025

Interior structure of black holes with nonlinear terms

We investigate the oscillation of the Kasner exponent $p_t$ near critical point of the hairy black holes dual to holographic superfluid and reveal a clear inverse periodicity $f(T_c/(T_c-T))$ in a large region below the critical temperature. We first introduce the fourth-power term with a coefficient $\lambda$ to adjust the oscillatory behavior of the Kasner exponent $p_t$ near the critical point. Importantly, we show that the nonlinear coefficient $\lambda$ provides accurate control of this periodicity: a positive $\lambda$ stretches the region, while a negative $\lambda$ compresses it. By contrast, the influence of another coefficient $\tau$ is more concentrated in regions away from the critical point. This work provides a new perspective for understanding the complex dynamical structure inside black holes and extends the actively control from the fourth- and sixth-power term into the black hole interior region.

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arXiv2025

Probing quantum anomaly corrections on black hole physics through chaos

The black hole horizon can induce chaotic motion of particles around the black hole. The original integrable motion of particles can transit to the chaotic motion when approaching black hole horizon. In this work, we consider the black hole background where quantum conformal anomaly correction is taken into account. We use Poincare section and Lyapunov exponent as representative probes to illustrate chaos. We investigate the effect of anomaly coefficient on the chaos of particles and for both probes, we find that quantum anomaly generally enhances the chaos of particle motions. As the chaotic orbits of particles can leave an imprint on the gravitational wave signals of the extreme mass ratio inspirals, our results pave the way to detect conformal anomaly effect in actual observations.

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arXiv2025

Interior structure of the holographic s + p superconductor and chaotic-stable transition near the black hole singularity

In this work, we investigate the interior structure of a holographic multi-band superconductor with the coexistence of s-wave and p-wave order parameters. Especially, we investigate the singularity structure of this multi-band model. Different from the single p-wave case, the alternation rule is jointly determined by parameters involving both s-wave order and p-wave order. In the coexistence region, we derive the Kasner alternation laws from both analytical and numerical methods which fit each other nicely. Furthermore, we find that the occurrence of the s-wave order parameter will lead to a chaotic-stable transition for the near singularity structure which matches the expectation of cosmological billiard approach. This novel transition for the near singularity structure constitutes a holographic counterpart of the secondary condensation in boundary superconducting system, offering a complementary perspective for characterizing the properties of boundary condensed matter systems.

hep-th↗

arXiv2025

Curled orbit and epicyclic oscillation of charged particles around the weakly magnetized black hole in the presence of Lorentz violation

In this paper, we investigate the motion of charged particles around the weakly magnetized Schwarzschild-like bumblebee black hole which has Lorentz symmetry breaking. Charged particles have curled orbits around the black hole which can only appear in the presence of external magnetic field. We investigate the effect of Lorentz violation factor on the curled orbit for both the case with and without cosmological constant. Furthermore, we investigate the harmonic oscillation behavior of the charged particles around the stable circular orbit. By using the epicyclic resonance model, we relate the harmonic oscillations of charged particles to the twin high frequency quasi-periodic oscillations observed in micro-quasars. Based on the observations of quasi-periodic oscillation, we provide a stringent constraint on the Lorentz violating parameters by using Markov Chain Monte Carlo algorithm. As the black hole shadow for Schwarzschild-like bumblebee black hole degenerates to the ordinary Schwarzschild black hole, the constraints we obtained from the quasi-period oscillation is crucial for further searching for the imprint of Lorentz symmetry breaking in our universe.

gr-qc↗

arXiv2024

Diving into a holographic multi-band superconductor

In this work, we investigate the interior structure of a holographic multi-band superconductor model. We focus on the holographic superconductor system with two scalar fields which correspond to two s-wave order parameters in the dual condensed matter system. We discover a new kind of transition rule among Kasner universe near the black hole singularity which is distinct from the holographic single-band superconductor model. This transition rule is the first generalization of Kasner transition behavior to scenarios involving multiple free parameters, which is useful for uncovering the most general interior structures of hairy black holes. Moreover, we find that the Kasner exponents are sensitive to the details of order parameters in boundary system. These different near singularity structures we found show that the black hole interior plays crucial role in characterizing the boundary dual condensed matter systems.

hep-th↗

arXiv2024

Einstein-Horndeski gravity and the ultra slowly evaporating black hole

In this work, we study the evaporation behaviors of asymptotically flat charged black holes in the Einstein-Horndeski gravity theory. Based on the thermodynamics of the Horndeski black hole, we present a physical understanding of the scalar charge of the Horndeski black hole and also clarify its connection to the Einstein vector theory. As the presence of non-minimal coupling, the evaporating behaviors of the Horndeski black hole are vastly different from the Reissner-Nordstrom (RN) black hole case. Due to the different spacetime and electric field structures, the evaporation rate of the Horndeski black hole will slow down at the late stage of evaporation and thus gain a lifetime much longer than the RN black hole. These results illuminate the effect of non-minimally coupled matters on the black hole evaporation and provide clues to search for these matter fields in future observations.

gr-qc↗

arXiv2024

Quantum anomaly triggers the violation of scaling laws in gravitational system

Scaling laws for critical phenomena take pivotal status in almost all branches of physics. However, as scaling laws are commonly guaranteed by the renormalization group theory, systems that violate them have rarely been found. In this letter, we demonstrate that gravitational system can break scaling laws. We derive this result through investigating phase transition and critical phenomenon in a gravitational system with quantum anomaly. For the first time, we outline the key conditions to violate the scaling laws in generic gravitational system viewed from the equation of state $P=P(T,V)$. Our results indicate that quantum effects can magnify the distinctiveness of gravity, which may be significant to understand the microscopic structure of spacetime.

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arXiv2024

Superradiance of rotating black holes surrounded by dark matter

In rotating black hole background surrounded by dark matter, we investigated the super-radiant phenomenon of massive scalar field and its associated instability.Using the method of asymptotic matching, we computed the amplification factor of scalar wave scattering to assess the strength of super-radiance. We discussed the influence of dark matter density on amplification factor in this black hole background. Our result indicates that the presence of dark matter has suppressive influence on black hole super-radiance. We also computed the net extracted energy to further support this result. Finally, we analyzed the super-radiant instability caused by massive scalar field using the black hole bomb mechanism and found that the presence of dark matter has no influence on the super-radiant instability condition.

gr-qc↗

arXiv2024

Notes on thermodynamics of Schwarzschild-like bumblebee black hole

In this work, we investigated the thermodynamics of Schwarzschild-like bumblebee black hole using Iyer-Wald covariant phase space formalism. With a non zero vacuum expectation value, the bumblebee field is responsible for spontaneously breaking the Lorentz symmetry. As the bumblebee field is non-minimally coupled to gravity, we showed that the thermodynamic variables will be different from the counterpart in Einstein gravity. Especially, by using Iyer-Wald formalism, we found that the black hole entropy also differs from the result obtained from Wald entropy formula. Like Horndeski gravity, this mismatch is due to the divergence of bumblebee one-form field at the horizon. After figuring out the thermodynamics, we also briefly discussed the evaporation behavior of Schwarzschild like bumblebee black hole. We found that although bumblebee field has no influence on the critical impact factor, it can influence the black hole evaporation time.

gr-qc↗

arXiv2023

Investigating shadow images and rings of the charged Horndeski black hole illuminated by various thin accretions

In this paper, we investigate the shadows and rings of the charged Horndeski black hole illuminated by accretion flow that is both geometrically and optically thin. We consider two types of accretion models: spherical and thin-disk accretion flow. We find that in both types of models, the size of the charged Horndeski black hole shadow decreases with the increase of the charge, and it decreases more slowly for the Reissner-Nordstr\"om (RN) black hole. In the spherical accretion flow model, we find that the increase of the charge of Horndeski black hole brightens the light ring around it, and it brightens more significantly in comparison with RN black hole. Due to the Doppler effect, the charged Horndeski black holes with accretion flow of radial motion have darker shadows than those with the static accretion flow, but the size of the shadow is not affected by accretion flow motion. In the thin disk-shaped accretion flow model, we find that the brightness of the light ring around the charged Horndeski black hole is dominated by the direct emission from the accretion flow, and the contribution from lensed rings is relatively small, and that from the photon rings is negligible. We also find that the ring brightness decreases as the charge of Horndeski black hole increases, and the decrease is more significant than that in the RN black hole case. Moreover, the radiation position of the accretion flow can affect the shadow size and the ring brightness of the charged Horndeski black hole.

gr-qc↗

arXiv2023

Thermodynamics and evaporation of perfect fluid dark matter black hole in phantom background

We present a novel interpretation of the thermodynamics of perfect fluid dark matter (PFDM) black hole based on Misner-Sharp energy, and then investigate its evaporation behavior. We find that the ratio between dark sector initial density and black hole horizon radius significantly influences black hole evaporation behaviors. We demonstrate that the presence of the dark sector can significantly extend the lifetime of a black hole which is similar to the Reissner-Nordstrom case. Our work reformulates the thermodynamics of PFDM black holes and points out the existence of long-lived black holes in the presence of the dark sector.

gr-qc↗

arXiv2022

JT Gravity from Partial Reduction and Defect Extremal Surface

We propose the three-dimensional bulk dual for Jackiw-Teitelboim gravity coupled with CFT$_2$ bath based on partial reduction. The bulk dual is classical AdS gravity with a defect brane which has small fluctuation in transverse direction. We derive full Jackiw-Teitelboim gravity action by considering the transverse fluctuation as a dilaton field. We demonstrate that the fine grained entropy computed from island formula precisely agrees with that computed from defect extremal surface. Our construction provides a Lorentzian higher dimensional dual for Jackiw-Teitelboim gravity and therefore offers a framework to study problems such as black hole information paradox as well as gravity/ensemble duality.

hep-th↗

arXiv2022

Interior Structure and Complexity Growth Rate of Holographic Superconductor from M-Theory

We study the interior dynamics of a top-down holographic superconductor from M-theory. The condense of the charged scalar hair necessarily removes the inner Cauchy horizon and the spacetime ends at a spacelike singularity. Although there is a smooth superconducting phase transition at the critical temperature, the onset of superconductivity is accompanied by intricate interior dynamics, including the collapse of the Einstein-Rosen bridge, the Josephson oscillations of the condensate, and the final Kasner singularity. We obtain analytically the transformation rule for the alternation of different Kasner epochs. Thanks to the nonlinear couplings of the top-down theory, there is generically a never-ending chaotic alternation of Kasner epochs towards the singularity. We compute the holographic complexity using both the complexity-action and the complexity-volume dualities. In contrast to the latter, the complexity growth rate from the complexity-action duality has a discontinuity at the critical temperature, characterizing the sudden change of the internal structure before and after the superconducting phase transition.

hep-th↗

arXiv2021

No Cauchy Horizon Theorem for Nonlinear Electrodynamics Black Holes with Charged Scalar Hairs

We prove a no Cauchy horizon theorem for general nonlinear electrodynamics black holes with charged scalar hairs. By constructing a radially conserved charged, we show that there is no inner Cauchy horizon for both spherical and planar symmetric cases, independent of the form of scalar potential and nonlinear electrodynamics. After imposing the null energy condition, we are also able to rule out the existence of the Cauchy horizon for the hyperbolic black holes. We take the Born-Infeld black hole as a concrete example to study the interior dynamics beyond the event horizon. When the contribution from the scalar potential can be neglected, the asymptotic near-singularity takes a universal Kasner form. We also confirm that the intricate interior dynamics is closely associated with the instability of the inner Cauchy horizon triggered by scalar hairs.

gr-qc↗

arXiv2020

What kind of "complexity" is dual to holographic complexity?

It is assumed that the holographic complexities such as the complexity-action (CA) and the complexity-volume (CV) conjecture are dual to complexity in field theory. However, because the definition of the complexity in field theory is still not complete, the confirmation of the holographic duality of the complexity is ambiguous. To improve this situation, we approach the problem from a different angle. We first identify minimal and genuin properties that the filed theory dual of the holographic complexity should satisfy without assuming anything from the circuit complexity or the information theory. Based on these properties, we propose a field theory formula dual to the holographic complexity. Our field theory formula implies that the complexity between certain states in two dimensional CFTs is given by the Liouville action, which is compatible with the path-integral complexity. It gives natural interpretations for both the CA and CV conjectures and identify what their reference states are. When applied to the thermo-field double states, it also gives consistent results with the holographic results in the CA conjecture: both the divergent term and finite term.

hep-th↗

arXiv2020

Magnetotransport and Complexity of Holographic Metal-Insulator Transitions

We study the magnetotransport in a minimal holographic setup of a metal-insulator transition in two spatial dimensions. Some generic features are obtained without referring to the non-linear details of the holographic theory. The temperature dependence of resistivity is found to be well scaled with a single parameter $T_0$, which approaches zero at some critical charge density $\rho_c$, and increases as a power law $T_0\sim|\rho-\rho_c|^{1/2}$ both in metallic $(\rho>\rho_c)$ and insulating $(\rho<\rho_c)$ regions in the vicinity of the transition. Similar features also happen by changing the disorder strength as well as magnetic field. By requiring a positive definite longitudinal conductivity in the presence of an applied magnetic field restricts the allowed parameter space of theory parameters. We explicitly check the consistency of parameter range for two representative models, and compute the optical conductivities for both metallic and insulating phases, from which a disorder-induced transfer of spectral weight from low to high energies is manifest. We construct the phase diagram in terms of temperature and disorder strength. The complexity during the transition is studied and is found to be not a good probe to the metal-insulator transition.

hep-th↗