arXiv subjects

David Kubiznak

Publications and source records attributed to David Kubiznak.

At least 19 recordsLinked to original sources

arXiv2026

Thermodynamics of Genuine Kerr-Bertotti-Robinson Black Holes

We propose a thermodynamic description of the genuine Kerr-Bertotti-Robinson (Kerr-BR) black hole spacetimes. Contrary to previous studies, such solutions no longer have electric charge. Consequently, the thermodynamics is governed by simple relations. Namely, upon introducing a suitable normalization factor for the timelike Killing vector, these spacetimes are characterized by the standard Hawking temperature, Bekenstein's entropy, Komar mass and angular momentum, and horizon angular velocity. The corresponding mass is shown to obey the standard Christodoulou-Ruffini formula, along with the standard first law and Smarr relations. In fact, by a proper rescaling of coordinates and solution parameters, and up to a non-trivial parameter space constraint, we formally recover the thermodynamic quantities of the vacuum Kerr solution. This is used to bring the genuine Kerr-BR spacetime into a Kerr-like form.

gr-qc↗

arXiv2026

On Generalized (Conformal) Killing Tensors

We study higher-rank generalized Killing tensors with mixed symmetries, providing a couple of examples and applications. It is shown that such objects naturally exist in higher-dimensional rotating black hole spacetimes, where they arise as partially contracted "squares" of Killing-Yano tensors and display interesting algebraic and differential properties. Motivated by conformal Killing tensors, a generalization of these objects that gives rise to parallel-transported tensors along null geodesics is proposed and shown to exist in higher-dimensional rotating black hole spacetimes.

gr-qc↗

arXiv2026

From (Hidden) Symmetries to Stealth Solutions

In a recent paper, Arxiv:2605.23077, we have demonstrated that (conformal) Killing vectors give rise to stealth vector solutions of a specific bumblebee-type Proca theory supplemented by fine tuned curvature terms. Here we show that such a construction readily generalizes to hidden symmetries encoded in (conformal) Killing-Yano tensors, giving rise to the corresponding p-form stealth solutions. Similar to what happens with Killing vectors, the construction works on any background, providing a "physical visualization" of its symmetries. Several examples of spacetimes with so constructed p-form stealth hair are presented.

gr-qc↗

arXiv2026

Proca-type Hair of Rotating Black Holes in Higher Dimensions

We show that spacetime symmetries on any background give rise to stealth vector fields obeying Proca-type equations supplemented by curvature terms. This observation, which is true for solutions of any theory of gravity and with arbitrary matter content, effectively promotes spacetime symmetries to "physical fields" whose characteristic property is that their backreaction on the geometry vanishes. In particular, this allows one to construct exact Proca hair charged and magnetized rotating black holes in all dimensions. In fact, such a construction is not limited to Killing vector fields and equally works for conformal Killing vectors and hidden symmetries encoded in Killing-Yano tensors.

hep-th↗

arXiv2026

Bertotti-Robinson and Bonnor-Melvin universes in nonlinear electrodynamics

We review the status of Birkhoff's theorem in the presence of nonlinear electrodynamics (NLE) - extending the analysis to the case without asymptotic flatness. This leads to the Bertotti-Robinson-type (direct product) geometry with generally unequal radii for its $AdS_{2}$ and $S_{2}$ factors, determined by a given NLE model. As can be expected, such a geometry can also be recovered from a near-horizon limit of the corresponding extremal NLE charged black hole (if it exists). These extremal black holes are shown to be linearly stable for specific NLE models, unlike in the Maxwell-$\Lambda$ case where unequal radii also arise in near-horizon geometry. Regular particle-like models are constructed by replacing the interior of these black holes with corresponding Bertotti-Robinson-type geometry. We also revisit the NLE generalization of the Bonnor-Melvin universe, describing a regular axisymmetric configuration of magnetic field lines in gravito-magnetic equilibrium. Explicit examples are derived for the Maxwell, Born-Infeld, RegMax, and Frolov-Hayward theories of electrodynamics.

gr-qc↗

arXiv2026

On mass inflation and thin shells in quasi-topological gravity

We study the null junction conditions in (re-summed) quasi-topological gravity theories, showing that no null thin shells exist within the realms of standard distributional theory for the pure gravity regular black hole solutions we have analyzed. This implies that the usual derivation of the mass inflation instability, which makes use of null thin shells, is not applicable in these theories. The problem of stability of inner horizons of regular black holes in quasi-topological gravity is hence still open and must be addressed with a more refined analysis, which does not rely on thin shells or the vacuum condition.

gr-qc↗

arXiv2025

Hidden symmetries and separability structures of Ovcharenko-Podolsk\'y and conformal-to-Carter spacetimes

Recently, a remarkable new class of spacetimes describing black holes immersed in a non-aligned electromagnetic field has been found. While still of type D, this class goes beyond the famous Pleba\'nski--Demia\'nski family. Here we demonstrate that the whole class admits a hidden symmetry encoded in the non-degenerate conformal Killing--Yano 2-form. Interestingly, as a direct consequence of non-alignment of the electromagnetic field and contrary to the Pleba\'nski--Demia\'nski class (where the field is aligned), such a symmetry no longer generates the full "tower of symmetries". Despite this, it enables one to separate variables in massless Hamilton--Jacobi, conformal wave, and massless Dirac equations, as well as allows one to tackle massless vector and tensor perturbations. These results provide a useful mathematical tool for discussing numerous (astrophysical) applications to be described by these metrics. Moreover, as we shall show, the novel spacetimes provide an interesting test-ground for studying the recently defined Penrose charges whose existence is intrinsically related to hidden rather than explicit symmetries.

gr-qc↗

arXiv2025

Excising Cauchy Horizons with Nonlinear Electrodynamics

Charged and/or rotating black holes in General Relativity feature Cauchy horizons, which indicate a breakdown of predictability in the theory. Focusing on spherically symmetric charged black holes, we remark that the inevitability of Reissner-Nordstrom Cauchy horizon is due to the divergent electromagnetic self-energy of point charges. We demonstrate that any causal theory of nonlinear electrodynamics that regularizes the point charge self-energy also eliminates Cauchy horizons for weakly charged black holes. These black holes feature one (event) horizon and a spacelike singularity, analogous to the Schwarzschild metric. An example with Born-Infeld electrodynamics illustrates how this gives rise to an upper bound on the charge, which we compare with known bounds.

gr-qc↗

arXiv2025

Rotating Carroll Black Holes: A No Go Theorem

Recently, there has been a lot of interest in Carroll black holes and in particular whether or not one could find a Carrollian analogue of a rotating black hole spacetime. Here we show that every stationary and axisymmetric solution (and thence also a black hole) of Carrollian general relativity in any number of $d>3$ dimensions is necessarily also static (up to a "topological rotation"). The case of $d=3$ dimensions is special. There, the topological rotation is important and one can have a rotating Carroll BTZ black hole, obtained from a static one by the Carroll boost accompanied by the re-identification of the angular coordinate, similar to what happens in the Lorentzian case. We also find a Carrollian analogue of an accelerating black hole, showing that Schwarzschild is not the only possible stationary and axisymmetric Carroll black hole in four dimensions. A generalization of the no go theorem to include Maxwell, dilatonic, and axionic matter fields is also discussed.

hep-th↗

arXiv2025

Cardy Entropy of Charged and Rotating Asymptotically AdS and Lifshitz Solutions with a Generalized Chern-Simons term

We consider a three-dimensional gravity model that includes (non-linear) Maxwell and Chern-Simons-like terms, allowing for the existence of electrically charged rotating black hole solutions with a static electromagnetic potential. We verify that a Cardy-like formula, based not on central charges but on the mass of the uncharged and non-spinning soliton, obtained via a double Wick rotation of the neutral static black hole solution, accurately reproduces the Bekenstein-Hawking entropy. Furthermore, we show that a slight generalization of this model, incorporating a dilatonic field and extra gauge fields, admits charged and rotating black hole solutions with asymptotic Lifshitz behavior. The entropy of these solutions can likewise be derived using the Cardy-like formula, with the Lifshitz-type soliton serving as the ground state. Based on these results, we propose a generalized Cardy-like formula that successfully reproduces the semiclassical entropy in all the studied cases.

hep-th↗

arXiv2024

Extremal Kerr-Schild Form

We propose a novel ansatz, where the full black hole geometry is written as a linear in mass perturbation of the associated extremal black hole base. Contrary to its "standard" version, the corresponding "extremal Kerr-Schild form" is no longer restricted to special algebraic type spacetimes, and is applicable to numerous black hole solutions with matter, such as the charged Kerr-NUT-(A)dS spacetimes, black holes of $D=5$ minimal gauged supergravity, or the charged dilaton-axion rotating solutions. This ansatz is likely to find its applications in black hole perturbation theory, shed new light on the CFT description of non-extremal black holes, as well as be useful for constructing new exact solutions.

gr-qc↗

arXiv2024

Love symmetry in higher-dimensional rotating black hole spacetimes

We develop a method for constructing a 1-parameter family of globally-defined Love symmetry generators in rotating black hole spacetimes of general dimension. The key ingredient is to focus on the vicinity of the (physical) outer horizon, matching only the radial derivative and the outer horizon pole pieces of the Klein--Gordon operator in the black hole spacetime to the $SL(2,\mathbb{R})$ Casimir operator. After revisiting the 4D Kerr and 5D Myers--Perry cases, the procedure is illustrated on generalized Lense--Thirring spacetimes which describe a wide variety of slowly rotating black hole metrics in any number of dimensions. Such spacetimes are known to admit an extended tower of Killing tensor and Killing vector symmetries and, as demonstrated in this paper, allow for separability of the massive scalar wave equation in Myers--Perry-like coordinates. Interestingly, separability also occurs in the horizon-penetrating Painlev{\'e}--Gullstrand coordinates associated with the freely infalling observer who registers flat space around her all the way to singularity.

gr-qc↗

arXiv2024

Regularized Conformal Electrodynamics: Novel C-metric in (2+1) Dimensions

Conformal electrodynamics is a particularly interesting example of power Maxwell non-linear electrodynamics, designed to possess conformal symmetry in all dimensions. In this paper, we propose a regularized version of Conformal electrodynamics, minimally regularizing the field of a point charge at the origin by breaking the conformal invariance of the theory with a dimensionfull "Born-Infeld-like" parameter. In four dimensions the new theory reduces to the recently studied Regularized Maxwell electrodynamics, distinguished by its "Maxwell-like" solutions for accelerated and slowly rotating black hole spacetimes. Focusing on three dimensions, we show that the new theory shares many of the properties of its four-dimensional cousin, including the existence of the charged C-metric solution (currently unknown in the Maxwell theory).

gr-qc↗

arXiv2024

Inner-extremal regular black holes from pure gravity

Recently it was shown that essentially all regular black hole models constructed so far can be obtained as solutions of vacuum gravity equations, upon considering an infinite series of quasi-topological higher curvature corrections. Here we show that such a construction can be upgraded to yield regular black holes with vanishing inner horizon surface gravity. In four dimensions, such a condition is necessary for the absence of classical instabilities associated with mass inflation on the inner horizon.

gr-qc↗

arXiv2024

Optical properties of black holes in regularized Maxwell theory

Regularized Maxwell electrodynamics is a recently discovered theory of non-linear electrodynamics, with a "minimally regularized" field strength of a point charge, that is "very close" to the Maxwell theory in many aspects. In this paper we investigate some of the optical properties of its black holes. Namely, we study geodesics, gravitational red-shift, black hole shadow, as well as investigate the relationship between the behavior of (null geodesic) Lyapunov exponents and the existence of thermodynamic critical points in both canonical and grand-canonical ensembles.

gr-qc↗

arXiv2024

Homogeneous Symmetry Operators in Kerr--NUT--AdS Spacetimes

It is well known that the Kerr--NUT--AdS spacetimes possess hidden symmetries encoded in the so-called principal Killing--Yano tensor. In this paper, focusing on the four-dimensional case, we obtain a number of symmetry operators for scalar, vector, and tensor perturbations, that are of degree two (to be defined below) and homogeneous in the principal tensor. In particular, by considering homogeneous operators that are linear, quadratic, and cubic in the principal tensor, we recover a complete set of 4 mutually commuting operators for scalar perturbations, underlying the separability of (massive) scalar wave equation. Proceeding to vector and tensor perturbations of the Kerr--NUT--AdS spacetimes, we find a set of 7 and 8 commuting operators, respectively. It remains to be seen whether such operators can be used to separate the corresponding spin 1 and spin 2 test field equations in these spacetimes.

gr-qc↗

arXiv2023

Holographic CFT Phase Transitions and Criticality for Rotating AdS Black Holes

Employing the novel exact dictionary between the laws of extended black hole thermodynamics and the laws of the dual CFT, we study the extended thermodynamics for CFT states that are dual to neutral singly-spinning asymptotically AdS black holes in $d$ bulk spacetime dimensions. On the field theory side we include two independent pairs of thermodynamic conjugate variables: the central charge-chemical potential term and the pressure-volume term. In this setting we uncover various phase transitions and critical behaviour in the CFT, focusing on three different thermodynamic ensembles. Namely, for fixed angular momentum and central charge, we show there is a Van der Waals-like criticality for $d=4,5$ and reentrant phase transitions for $d\ge 6$. At fixed angular velocity and central charge, there is a first-order (de)confinement phase transition in all dimensions $d \ge 3$. Finally, at fixed angular momentum and chemical potential we find a plethora of zero-order phase transitions and unstable phases in both $d=4$ and $d=6$.

hep-th↗

arXiv2023

Solutions and basic properties of regularized Maxwell theory

The regularized Maxwell theory is a recently discovered theory of non-linear electrodynamics that admits many important gravitating solutions within the Einstein theory. Namely, it was originally derived as the unique non-linear electrodynamics (that depends only on the field invariant $F_{\mu\nu}F^{\mu\nu}$) whose radiative solutions can be found in the Robinson--Trautman class. At the same time, it is the only electrodynamics of this type (apart from Maxwell) whose slowly rotating solutions are fully characterized by the electrostatic potential. In this paper, after discussing the basic properties of the regularized Maxwell theory, we concentrate on its spherical electric solutions. These not only provide `the simplest' regularization of point electric field and its self-energy, but also feature complex thermodynamic behavior (in both canonical and grandcanonical ensembles) and admit an unprecedented phase diagram with multiple first-order, second-order, and zeroth-order phase transitions. Among other notable solutions, we construct a novel C-metric describing accelerated AdS black holes in the regularized Maxwell theory. We also present a generalization of the regularized Maxwell Lagrangian applicable to magnetic solutions, and find the corresponding spherical, slowly rotating, and weakly NUT charged solutions.

gr-qc↗