Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · 2610.36129

Unified Dynamics of Black-Hole Interiors: From Geometric to Scalar-Kinetic Dominance

Fu-Guo Yang
View original source ↗Read source document ↗Export metadata ↓

Abstract

We identify a unified dynamical picture connecting small-amplitude scalar input at the event horizon to scalar--Kasner interiors. Within boundary-supported stationary families, area contraction drives the transition from geometric to scalar kinetic dominance. For the Schwarzschild-like branch, contraction suppresses the relative curvature contribution, so the scalar kinetic term becomes dominant while the gradient remains small. For the Kerr--Newman-like branch, the scalar gradient is strongly amplified as area contraction carries the solution toward the would-be Cauchy-horizon zero, followed by a narrow transition to scalar kinetic dominance. Cancellation between the kinetic and geometric terms produces a positive minimum of a metric diagnostic, explaining inner-horizon loss dynamically. Fully coupled numerical solutions for the Schwarzschild-like branch and four-dimensional stationary axisymmetric Kerr--Newman interiors, including the Reissner--Nordström and Kerr limits, support this picture. Area contraction provides the common physical mechanism, while the would-be Cauchy-horizon zero determines the strength of gradient amplification and the localization of the transition.

Explore related subjects

gr-qc

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Fu-Guo Yang. 2026-10-26. Unified Dynamics of Black-Hole Interiors: From Geometric to Scalar-Kinetic Dominance. https://arxiv.org/abs/2610.36129

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Testing Conformal Weyl Gravity with Plasma Modified Black Hole Shadows and EHT Constraints

We study the shadows of a charged rotating de Sitter solution in fourth order conformal Weyl gravity (CWG) immersed in plasma and analyze the joint charge-plasma constraints. Our main goal is to distinguish observational effects caused by the dispersive plasma environment from those caused by the underlying gravitational theory. Within a separable Hamilton-Jacobi plasma model, we derive the radial and angular photon potentials, the equatorial finite-distance deflection angle, and the finite-observer shadow boundary due to the asymptotically non-flat nature of the CWG spacetime. Our results separate two effects. Increasing the plasma strength generally reduces the shadow radius, the signed deflection angle, and the energy emission peak in both CWG and GR. Charge ($q$) produces a stronger theory dependence: for the representative parameters studied, increasing $q$ enlarges the CWG shadow but reduces the GR shadow. The lensing behavior independently supports the geometry-dependent response found from the photon region and shadow observables. We further compare the finite observer dimensionless shadow radius with EHT-inferred size intervals for Sgr~A$^*$ and M87$^*$. Our results indicate that plasma effects can mimic part of the shadow size shift, but the distinct charge response of CWG offers a potential observational route for separating conformal gravity signatures from environmental propagation effects.

gr-qc↗
arXiv2026

Classical and Semiclassical Stability of Emergent Universes in Jordan-Brans-Dicke Theory

The Emergent Universe scenario is based on the assumption that the universe originates from a past-eternal Einstein static (ES) state, subsequently evolving toward an inflationary phase and a hot Big Bang era. Such models are appealing as they provide nonsingular and geodesically complete cosmological histories. However, it has been argued by Mithani and Vilenkin that, even when the ES state is classically stable, certain models can admit semiclassical tunneling channels leading to quantum decay toward configurations of vanishing scale factor. In this work, we investigate the classical and semiclassical stability of the ES regime in the context of Jordan-Brans-Dicke (JBD) theory. We analyze the structure of the Wheeler-DeWitt potential in minisuperspace and study representative semiclassical tunneling channels compatible with the Hamiltonian constraint. We show that, for suitable choices of the JBD potential and model parameters, the ES configuration can be robust against both classical perturbations and the specific semiclassical tunneling channels analyzed in this work. Our results indicate that the quantum instability discussed by Mithani and Vilenkin may be avoided within certain regions of parameter space, while leaving open the possibility of more general tunneling processes beyond the scope of the present analysis.

gr-qc↗
arXiv2026

Minimum lifetime of a black hole

We derive bounds on the lifetime of an evaporating black hole. The minimum lifetime bound follows from energy conservation and purification, within the framework of `asymptotically semiclassical spacetimes'. The recently derived expression for the Bondi flux of Hawking radiation, together with the expression for the entanglement entropy of Hawking radiation at null infinity, is used to investigate the purification phase after the last semiclassical ray. We discuss the energy-cost of entanglement purification and find a lower bound on the purification time of the black hole, which scales as $M_0^4/\hbar^{3/2}$, where $M_0$ is the initial black hole mass. Additionally, motivated by the Planck luminosity bound in quantum gravity, we include the additional assumption that a Planck mass black hole is metastable. With this assumption, the purification time is in fact exponential in the square of the initial black hole mass, $τ\sim\sqrt{\hbar}\,\exp(γM_0^2/\hbar)$ with $γ>0$, i.e., exponential in its initial area. We find that the redshift exponent is negative in this purification phase, which indicates the existence of a white-hole remnant that releases information slowly. We comment on phenomenological implications for primordial black hole remnants.

gr-qc↗