arXiv subjects

Run-Qiu Yang

Publications and source records attributed to Run-Qiu Yang.

At least 19 recordsLinked to original sources

arXiv2026

Curvature-Induced Geometric Universality in Non-Hermitian Anderson Transitions

In Euclidean space, universality classes of Anderson transitions are primarily determined by symmetry and spatial dimensionality. Here, we present evidence for a geometry-controlled universality class of non-Hermitian Anderson transitions on hyperbolic-like lattices. In this setting, critical behavior is influenced by the large-scale hyperbolic geometry, characterized by negative curvature, exponential volume growth, and a non-Euclidean notion of spatial scaling. Finite-size scaling of participation ratios across several distinct $ \{p,q\} $ tilings reveals one-parameter scaling collapses with a common critical exponent $ \nu\simeq1 $ within numerical accuracy. A complementary phenomenological coarse-grained Landau-Ginzburg analysis shows how exponential correlation-volume growth suppresses critical fluctuations, offering a rationale for the observed mean-field-like scaling. Our results suggest that spatial curvature can act as an additional organizing principle for Anderson-transition universality beyond the conventional dimensionality- and symmetry-based classification.

cond-mat.dis-nn↗

arXiv2026

Stability of a black hole under the deformation of an extended periodic potential

It has been shown that the spectrum of black hole quasi-normal modes is extremely sensitive to localized deformations of the geometry away from the potential peak. The deformation caused by a real astronomical environment will extend throughout the whole space rather than be localized in a finite region. Whether spatially extended fluctuations distributed throughout spacetime can produce similar effects remains unclear. In this work, we construct a toy model to investigate the case that the deformation of the metric is not localized but extends throughout the whole space. We study how it changes the ringdown stage of the black hole in the time domain. Using both the P\"oschl-Teller and Regge-Wheeler potentials as representative backgrounds, we show that sufficiently wide spatially periodic perturbations of zero mean can trigger not only the ``spectral instability'' in the frequency domain but also black hole instabilities in the time domain. Through numerical analysis, we uncover a universal scaling relation for the instability threshold and further provide an analytical interpretation of its physical origin.

gr-qc↗

arXiv2026

Linear Growth of Holographic Time-like Entanglement Entropy and Kasner exponents

The holographic time-like entanglement entropy (TEE) extends entanglement to time-like boundary subregions. While its definitive holographic dictionary remains debated, one concrete proposal utilizes piece-wise extremal surfaces. In this work, we adopt this geometric prescription as an exploratory framework to holographically investigate the late-time ($\tau_0\to \infty$) growth of TEE in asymptotically AdS black holes with a space-like singularity and no inner horizon. By assuming a Kasner geometry near the space-like singularity and using the null energy condition, we analytically show that a critical extremal surface $\mathcal{A}_c$ inside the event horizon completely governs the late-time linear growth of the TEE. This result suggests that the late-time behavior of TEE is tightly constrained by the geometry of black hole interiors. While the dominant energy condition (DEC) guarantees an upper bound for the real part's growth rate, we conjecture a corresponding universal lower bound for the imaginary part. Numerical results from Einstein-scalar theory demonstrate the robustness of this bounding behavior: the vacuum Schwarzschild-AdS geometry consistently maximizes the real growth rate and minimizes the imaginary part, suggesting these bounds hold in broader holographic setups.

hep-th↗

arXiv2026

Near-Horizon Deformation of Metric and the Black Hole Instability

Recent time-domain analyses suggest that black hole stability may be sensitive to localized near-horizon geometric deformations, while the underlying spectral mechanism remains unclear. In this work, we systematically investigate quasi-normal mode spectra under static localized non-positive perturbations within a frequency-domain framework. We find that such deformations generically induce a new purely imaginary mode. As the deformation approaches the horizon, the imaginary part of this mode increases and eventually enters the upper half complex-frequency plane, signaling the onset of black hole instability. Numerical results reveal clear scaling relations between the critical distance for instability and the deformation strength. We further derive rigorous proofs for our discoveries in frequency domain. These results demonstrate that black hole stability under long scale is conditionally sensitive to localized deformation of metric near the horizon and establish a unified spectral framework for understanding their induced instabilities.

gr-qc↗

arXiv2026

Black Hole Interior and Time-like Entanglement Entropy

We establish time-like entanglement entropy (TEE) as a novel tool to characterize the black hole interior from a single-boundary perspective. In the Schwarzschild-AdS black hole, we show that TEE of time-like boundary strips exhibits linear growth as a function of temporal width in the limit of large temporal width, and that its imaginary part carries physical significance rather than being a constant. By analyzing charged, scalar-hairy black holes, we present evidence that TEE detects a hidden "causal phase transition" separating Type-I and Type-II interiors -- distinguished by singularity structure. We identify a critical temporal width $\tau_c$ that acts as the order parameter for this transition: for strips narrower than $\tau_c$, the system enters a distinct "time-like entanglement phase" dominated purely by time-like contributions, up to a regulator effect; conversely, for strips wider than $\tau_c$, space-like entanglement re-emerges. Notably, the existence of a Cauchy horizon drives the $\tau_c$ to infinity, leading to pure time-like entanglement. These results suggest that the TEE may supply a novel boundary quantum-information measure to detect structure hidden inside the black hole and suggests a deep connection between TEE and cosmic censorship.

hep-th↗

arXiv2026

Quantization-scheme-Independent Energy and Its Implications for Holographic Bounds

In holographic duality, the total energy of the dual field theory is obtained from the holographic renormalization, which depends not only on the bulk geometry but also on the choice of quantization schemes. We point out that the validity of several widely studied holographic inequalities -- including the AdS Penrose inequality, the late-time bound on entanglement entropy growth, and the growth-rate limits of CV and CA complexities -- depends on the choice of quantization schemes. Motivated by this issue, we introduce a modified total energy, which is still computed via holographic renormalization but the final value is independent of the choice of quantization schemes. We verify that this modified energy removes the apparent violations of these bounds that arise from quantization-scheme dependence in the model of massive scalar field. Our results suggest that our modified total energy provides a more robust notion of energy when we talk about above inequalities in holographic settings.

hep-th↗

arXiv2025

Application of Solving Inverse Scattering Problem in Holographic Bulk Reconstruction

We investigate the problem of bulk metric reconstruction in holography by leveraging the inverse scattering framework applied to boundary two-point correlation functions. We generalize our previous work of scalar field and show that reconstruction can be achieved using a single operator rather than a pair. We also apply this method into reconstruction of static homogeneous anisotropic black holes and the reconstruction using correlation function of gauge field. In addition, we analyze the method's robustness under measurement noise and propose filtering strategies to improve reconstruction accuracy. This work advances data-driven bulk reconstruction by providing a concrete, experimentally viable pathway to recover spacetime geometry from field-theoretic observables.

hep-th↗

arXiv2025

Numerical study on the robustness of the stability for stable black holes

This paper numerically studies if the stability of a stable black hole is robust against the small perturbation on geometry near its event horizon. In an other word, we numerically study if two nearly identical black holes may exhibit completely different stabilities at late time. As a toy model, it encodes the such perturbation into deformations of Regge-Wheeler potential. It considers three different types of local deformations-the negative static bump potential, the stochastic potential and bump potential modulated by time function in low frequency limit. Our numerical results show that infinitesimal local deformations on Regge-Wheeler potential near the horizon can overturn stability of a stable black hole, implying that late-time behavior of a stable black hole is extremely sensitive to geometry near horizon. Specially, certain deformations that stabilize systems in flat backgrounds can destabilize otherwise stable black holes. It also shows that horizon-induced redshift transforms near-horizon quantum fluctuations into classical-scale stochastic deformations capable of triggering instability, implying that even an isolated black hole cannot keep stable if the near-horizon quantum noise could be hold in extended timescales.

gr-qc↗

arXiv2024

Simulation of the massless Dirac field in 1+1D curved spacetime

Simulating the nature of quantum fields in diverse spacetime backgrounds offers valuable insights for the fundamental comprehension of quantum mechanics and general relativity. Here we introduce a novel method for mapping the massless Dirac equation in 1+1D curved spacetime to a controllable quantum simulation model, applicable to various observers' perspectives. We perform numerical simulations of Simpson spacetime and calculate tunneling rates in Painleve and Schwarzschild coordinates, which align closely with theoretical predictions of Hawking radiation. Additionally, we show the transition of Simpson spacetime from a regular black hole to a wormhole as the parameter $"a > r_s"$. This method facilitates the study of spacetime from various coordinate perspectives (observers), providing deeper insights and understanding.

gr-qc↗

arXiv2024

Geodesics connecting end points of time-like interval in asymptotically AdS spacetime

This paper studies the geodesics connecting two time-like separated boundary points in asymptotically anti-de Sitter (AdS) spacetime. We find that in spherically symmetry Schwarzschild AdS black hole, smooth space-like geodesics can connect timelike-separated points by winding around the horizon multiple times. Similar result will also happen in modified BTZ black hole which contains photon ring in the bulk. According to recent holographic proposal on time-like entanglement entropy, our result suggests that, if there is photon ring/sphere in the bulk, then the time-like entanglement entropy AdS3/CFT2 duality may not have an imaginary part and so further understanding may be necessary.

hep-th↗

arXiv2024

Spectral instability of black holes: relating the frequency domain to the time domain

Recent work has shown that the quasinormal mode spectrum of black holes is unstable under small perturbations (of order $\epsilon$) of the radial potential, while the early time-domain ringdown waveform is only marginally affected. In this paper we provide further insight into the apparent tension between the frequency-domain and the time-domain descriptions by analyzing the scattering properties of the problem. In the frequency domain, we study analytically the solutions corresponding to the perturbed potential. We show that there are two qualitatively different classes of instabilities, and that both Schwarzschild and Kerr black holes are affected by what we call a "Type II" instability, i.e., an exponential migration of the mode frequencies away from their unperturbed value as the perturbing "bump" moves away from the peak of the unperturbed potential. In the time domain, we elucidate the effect of the spectral instability in terms of the causal structure of the Green's function. By using an equivalent scattering problem we confirm analytically (and show numerically) that the deviation from the unperturbed waveform in the early ringdown stage is proportional to $\epsilon$ when $\epsilon\lesssim10^{-2}$.

gr-qc↗

arXiv2023

Inverse problem of correlation functions in holography

This paper shows that the bulk metric of a planar/spherically/hyperbolically symmetric asymptotically anti-de Sitter static black brane/hole can be reconstructed from its boundary frequency 2-point correlation functions of two probe scalar operators by solving Gel'fand-Levitan-Marchenko integral equation. Since the frequency correlation function is easily handled in experiments and theories, this paper not only proposes a new method to ``measure'' the corresponding holographic spacetime for a material that has holographic dual but also provides an approach to experimentally check if a system has holographic dual.

hep-th↗

arXiv2023

Holographic quantum distances and replica trick

This paper gives concrete examples to exhibit how to use the replica trick to calculate the quantum (quasi-)distances holographically. First, we consider the fidelity and relative entropy between thermal states that are dual to the Schwarzschild-AdS black holes. Then we generalize our method into the RN-AdS black holes by adding a U(1) gauge field. We also investigate the fidelity between states excited by scalar operator in probe limit. In this case, it is surprising that the fidelity in standard quantization will suffer from new UV divergence though the usual holographic renormalization has been applied. We call for deep understanding for such divergence in the future. We also discover a holographic method to check whether the density matrices of two holographic states are commutative.

hep-th↗

arXiv2023

Testing holographic duality in hyperbolic lattices

The celebrated holographic duality posits a correspondence between a quantum gravity in a bulk spacetime and a quantum field theory (QFT) defined on its lower-dimensional boundary. This duality not only offers deep insights into the enigmatic nature of quantum gravity but also provides an efficient methodology for studying strongly correlated systems. However, despite its profound significance in modern physics, holographic duality remains a conjecture, and further experimental exploration is highly sought after. Here, we present the first experimental test of holographic duality between a three-dimensional bulk gravity and a two-dimensional boundary QFT using hyperbolic lattices. By experimentally measuring the classical scalar field propagator in hyperbolic circuits, we reproduce the equal-time two-point correlation function of the dual boundary conformal field theory (CFT), verifying its exponential dependence on the boundary separation and the conformal dimension-scalar mass relation. Furthermore, by leveraging the two-point correlation function, we reconstruct the entanglement entropy for a boundary CFT subsystem, confirming that it follows the Ryu-Takayanagi formula. These results constitute the first direct experimental evidence that quantum properties of the QFT can be holographically reproduced through its dual classical field in curved space. This heuristic experimental effort opens a new avenue for in-depth investigations on the holographic duality and extensive exploration of quantum-gravity-inspired phenomena in classical systems.

hep-lat↗

arXiv2022

On holographic time-like entanglement entropy

In order to study the pseudo entropy of time-like subregions holographically, the previous smooth space-like extremal surface was recently generalized to mix space-like and time-like segments and the area becomes complex value. This paper finds that, if one tries to use such kind of piecewise smooth extremal surfaces to compute time-like entanglement entropy holographically, the complex area is not unique in general. We then generalize the original holographic proposal of space-like entanglement entropy to pick up a unique area from all allowed ``space-like+time-like'' piecewise smooth extremal surfaces for a time-like subregion. We will give some concrete examples to show the correctness of our proposal.

hep-th↗

arXiv2022

Using black holes as rechargeable batteries and nuclear reactors

This paper proposes physical processes to use a Schwarzschild black hole as a rechargeable battery and nuclear reactor. As a rechargeable battery, it can at most transform 25\% of input mass into available electric energy in a controllable and slow way. We study its internal resistance, efficiency of discharging, maximum output power, cycle life and totally available energy. As a nuclear reactor, it realizes an effective nuclear reaction ``$\alpha$ particles+black hole$\rightarrow$positrions+black hole'' and can transform 25\% mass of $\alpha$-particle into the kinetic energy of positrons. This process amplifies the available kinetic energy of natural decay hundreds of times. Since some tiny sized primordial black holes are suspected to have an appreciable density in dark matters, the result of this paper implies that such black-hole-originated dark matters can be used as reactors to supply energy.

gr-qc↗

arXiv2022

Tightening the Penrose Inequality

The Penrose inequality estimates the lower bound of the mass of a black hole in terms of the area of its horizon. This bound is relatively loose for extremal or near extremal black holes. We propose a new Penrose-like inequality for static black holes involving the mass, area of the black hole event horizon and temperature. Our inequality includes the Penrose inequality as its corollary, and it is saturated by both the Schwarzschild and Reissner-Nordstr\"om black holes. In the spherically-symmetric case, we prove this new inequality by assuming both the null and trace energy conditions.

gr-qc↗

arXiv2022

Upper bounds of holographic entanglement entropy growth rate for thermofield double states

We studied the upper bounds of the holographic entanglement entropy growth rate for thermofield double (TFD) states. By comparing the cases of vacuum AdS and charged AdS black holes, we conjecture: for all static planar or spherically symmetric asymptotically Schwarzschild-AdS black holes of same mass density or entropy density, the vacuum AdS black hole gives the maximum entanglement entropy growth rate. We gave proofs by assuming dominant energy condition. We also considered the AdS black hole spacetime with real scalar fields case, where the scalar fields violate the dominant energy condition and the bulk geometry is not asymptotically Schwarzschild-AdS. Numerical results show that this case vacuum black hole still has maximal growth rate if we fixed entropy. However, in the case of fixed energy, vacuum case has maximal growth rate of entanglement entropy only under standard quantization scheme.

hep-th↗