Møller's energy of the Kerr-NUT Metric

Algorithmic characterization results for the Kerr-NUT-(A)dS space-time. I. A space-time approach

We provide an algorithm to check whether a given vacuum space-time $(\mathcal{M},g)$ admits a Killing vector field w.r.t. which the Mars-Simon tensor vanishes. In particular, we obtain an algorithmic procedure to check whether $(\mathcal{M},g)$ is locally isometric to a member of the Kerr-NUT-(A)dS family. A particular emphasis will be devoted to the Kerr-(A)dS case.

Inner-most stable circular orbits in extremal and non-extremal Kerr-Taub-NUT spacetimes

We study causal geodesics in the equatorial plane of the extremal Kerr-Taub-NUT spacetime, focusing on the Innermost Stable Circular Orbit (ISCO),and compare its behaviour with extant results for the ISCO in the extremal Kerr spacetime. Calculation of the radii of the direct ISCO, its Kepler frequency, and rotational velocity show that the ISCO coincides with the horizon in the exactly extremal situation. We also study geodesics in the strong {\it non}-extremal limit, i.e., in the limit of vanishing Kerr parameter (i.e., for Taub-NUT and massless Taub-NUT spacetimes as special cases of this sp…

Electromagnetic emissions from near-horizon region of an extreme Kerr-Taub-Nut black hole

We have studied electromagnetic line emissions from near-horizon region in the extremal Kerr-Taub-NUT black hole spacetime and then probe the effects of NUT charge on the electromagnetic line emissions. Due to the presence of the NUT charge, the equatorial plane is no more a symmetry plane of the KTN spacetime, which leads to that the dependence of electromagnetic line emission on the NUT charge for the observer in the Southern Hemisphere differs from that in the Northern one. Our result indicate that the electromagnetic line emission in the Kerr-Taub-NUT black hole case is brighter than that …

Projectively non-singular horizons in Kerr-NUT-de Sitter spacetimes

It was recently discovered that Killing horizons in the generic Kerr-NUT-(anti) de Sitter spacetimes are projectively singular, i.e. their spaces of the null generators have singular geometry. Only if the cosmological constant takes the special value determined by the Kerr and NUT parameters, and the radius of the horizon, then the corresponding horizon does not suffer that problem. In the current paper, the projectively non-singular horizons are investigated. They are found to be cosmological and non-extremal. Every projectively non-singular horizon can be used to define a global completion o…

克尔-NUT热力学：米斯纳弦与努特荷

Kerr-NUT Thermodynamics: Misner Strings and Nut Charges

该研究将2206.09124的热力学方法应用于克尔-NUT解，发现与角动量对偶的新守恒量，补充了满足所有热力学关系的相关电荷，完善了克尔-NUT热力学的理论框架。

Magnetized Kerr-Newman-Taub-NUT spacetimes

We find a new class of exact solutions in the Einstein-Maxwell theory by employing the Ernst magnetization process to the Kerr-Newman-Taub-NUT spacetimes. We study the solutions and find that they are regular everywhere. We also find the quasilocal conserved quantities for the spacetimes, the corresponding Smarr formula and the first law of thermodynamics.

String-Dust Distributions with the Kerr-NUT symmetry

We attempt to solve the Einstein equations for string dust and null flowing radiation for the general axially symmetric metric, which we believe is being done for the first time. We obtain the string-dust and radiating generalizations of the Kerr and the NUT solutions. There also occurs an interesting case of radiating string-dust which arises from string-dust generalization of Vaidya's solution of a radiating star.

Zeeman-type dragging in the Kerr--Newman and NUT spacetimes

In this communication we discuss two distinct Zeeman-type gravitomagnetic effects deserving attention since they can be easily characterized in their exact form, not via approximation procedures. Some observations are also made on gravitoelectric effects.

Hidden conformal symmetry and pair production near the cosmological horizon in Kerr-Newman-Taub-NUT-de Sitter spacetime

We show that the study of hidden conformal symmetry that associates to the Kerr/CFT correspondence can also apply to the cosmological horizon in Kerr-Newman-Taub-NUT-de Sitter spacetime. This symmetry allows one to employ some two dimensional conformal field theory methods to understand the properties of the cosmological horizon. The entropy can be understood by using the Cardy formula, and the equation for scattering process in the near region has an agreement with the one obtained from a two point function in two dimensional conformal field theory. We also show that pair production can occur…

Equatorial Bañados-Silk-West effect in Kerr-Newman-Taub-NUT spacetime revisited

In this paper, we revisit the possibilities of Bañados-Silk-West (BSW) effect in Kerr-Newman-Taub-NUT (KNTN) spacetime for two neutral particles moving over the equatorial plane and constant $θ$ in Boyer-Lindquist coordinate. Contrary to a previous study on this topic, we found that BSW effect for two particles confined to move over the equatorial plane is not possible. Numerical calculations shows that BSW effect in constant $θ$ geodesics is possible under certain circumstances.

Separability of the Hamilton-Jacobi equation and equatorial circular photon orbit in Kerr-Sen-Taub-NUT spacetime

In this paper, we show the additive separation of the Hamilton-Jacobi equation, present the 4-velocity of the test particles, and attempt to find the equatorial circular photon orbit (ECPO) in the Kerr-Sen-Taub-NUT (KSTN) solution of the low energy limit of heterotic string theory. In the process of trying to find the ECPO, we instead encounter a ring singularity that could be outside the horizon of the KSTN black hole.

Kerr-Sen-Taub-NUT spacetime and circular geodesics

We present a novel solution obeying classical equation of motion in the low energy limit of heterotic string theory. The solution represents a rotating mass with electric charge and gravitomagnetic monopole moment. The corresponding conserved charges are discussed. We also study the test body circular equatorial motions in the spacetime.

Center of Mass Energy of the Collision for Two General Geodesic Particles Around a Kerr-Newman-Taub-NUT Black Hole

In this paper, we investigate the center of mass energy of the collision for two neutral particles with different rest masses falling freely from rest at infinity in the background of a Kerr-Newman-Taub-NUT black hole. Further, we discuss the center of mass energy near the horizon(s) of an extremal and non-extremal Kerr-Newman-Taub-NUT black hole and show that an arbitrarily high center of mass energy is achievable under some restrictions. We will study the special case of the center of mass energy when the specific energy, specific angular momentum and Carter constant of both the particles ar…

Kerr-Newman-Taub-NUT 时空中光传播的引力法拉第旋转

Gravitational Faraday rotation of light propagation in the Kerr-Newman-Taub-NUT space-time

本文在弱偏转极限下研究 Kerr-Newman-Taub-NUT 时空中的引力法拉第效应，发现源和观测者远离黑洞时仍存在非零旋转角，其大小取决于黑洞自旋、质量、观测者角位置以及电荷和 NUT 电荷。

Photon Regions and Shadows of Kerr-Newman-NUT Black Holes with a Cosmological Constant

We consider the Plebański class of electrovacuum solutions to the Einstein equations with a cosmological constant. These space-times, which are also known as the Kerr-Newman-NUT-(anti-)de Sitter space-times, are characterized by a mass $m$, a spin $a$, a parameter $β$ that comprises electric and magnetic charge, a NUT parameter $\ell$ and a cosmological constant $Λ$. Based on a detailed discussion of the photon regions in these space-times (i.e., of the regions in which spherical lightlike geodesics exist), we derive an analytical formula for the shadow of a Kerr-Newman-NUT-(anti-)de Sitter bl…

Rotating relativistic thin disks as sources of charged and magnetized Kerr-NUT spacetimes

A family of models of counterrotating and rotating relativistic thin discs of infinite extension based on a charged and magnetized Kerr-NUT metric are constructed using the well-known "displace, cut and reflect" method extended to solutions of vacuum Einstein-Maxwell equations. The metric considered has as limiting cases a charged and magnetized Taub-NUT solution and the well known Kerr-Newman solutions. We show that for Kerr-Newman fields the eigenvalues of the energy-momentum tensor of the disc are for all the values of the parameters real quantities so that these discs do not present heat f…

Kerr-Taub-NUT黑洞的Von Neumann熵的时间演化

Time evolution of Von Neumann entropy for a Kerr-Taub-NUT black hole

本文研究了Kerr-Taub-NUT黑洞蒸发发射标量粒子时的演化，发现辐射会增加角动量损失率并降低质量与NUT参数损失率，且其Von Neumann熵近似遵循Page曲线，高$β$值会加速蒸发过程。

带有Manko-Ruiz参数的Kerr-Sen-Taub-NUT黑洞阴影

Shadows for Kerr-Sen-Taub-NUT black holes with Manko-Ruiz parameter

本文探究含Manko-Ruiz参数的Kerr-Sen-Taub-NUT时空，证明测试粒子哈密顿-雅可比方程可分离并推导黑洞阴影边界方程，揭示时空参数（含Manko-Ruiz参数）对阴影形状的影响，为该时空几何研究提供新见解。

Kerr-Taub-NUT黑洞时空中的重复Penrose过程

Repetitive Penrose Process in Kerr-Taub-NUT black hole spacetime

研究Kerr-Taub-NUT黑洞中的重复Penrose过程，分析引力磁电荷对事件视界和能层半径的影响，以及通过守恒定律和迭代停止条件计算可提取能量的变化。

Kerr-Taub-NUT 时空中的二阶变化与超旋问题

Second order variations and the overspinning problem in Kerr-Taub-NUT spacetime

本文通过评估 Sorce-Wald 条件并计算面积的二阶变化，证明二阶变化能驱使 Kerr-Taub-NUT 黑洞偏离极端状态，从而避免超旋并保留事件视界，符合宇宙审查猜想。

Separability and Hidden Symmetries of Kerr-Taub-NUT Spacetime in Kaluza-Klein Theory

The Kerr-Taub-NUT spacetime in the Kaluza-Klein theory represents a localized stationary and axisymmetric object in four dimensions from the Kaluza-Klein viewpoint. That is, it harbors companion electromagnetic and dilaton fields, thereby showing up the signature of the extra fifth dimension. We explore the separability structure of this spacetime and show that the Hamilton-Jacobi equation for geodesics admits the complete separation of variables only for massless geodesics. This implies the existence of the hidden symmetries in the spacetime, which are generated by the conformal Killing tenso…

The trajectory of light ray under Kerr-Taub-NUT space time

According to General Relativity, there are three factors namely mass, rotation and charge that can influence the path of light ray. Many authors showed that there is another factor which can influence the path of light ray namely gravitomagnetism. Here we discuss the effect of a rotating body with non-zero (Kerr- Taub-NUT) magnetic field on the motion of light ray. We use the null geodesic of photon method and obtain the deflection angle of light ray for such a body up to fourth order term in the equatorial plane. Our calculation shows that magnetism has a noticeable effect on the path of ligh…

On symmetry operators for the Maxwell equation on the Kerr-NUT-(A)dS spacetime

We focus on the method recently proposed by Lunin and Frolov-Krtouš-Kubizňák to solve the Maxwell equation on the Kerr-NUT-(A)dS spacetime by separation of variables. In their method, it is crucial that the background spacetime has hidden symmetries because they generate commuting symmetry operators with which the separation of variables can be achieved. In this work we reproduce these commuting symmetry operators in a covariant fashion. We first review the procedure known as the Eisenhart-Duval lift to construct commuting symmetry operators for given equations of motion. Then we apply this pr…

Kerr-Newman Taub-NUT黑洞的黑洞热力学第一定律与弱宇宙监督猜想

First law of black hole thermodynamics and the weak cosmic censorship conjecture for Kerr-Newman Taub-NUT black holes

本研究构建了Kerr-Newman Taub-NUT黑洞自洽的热力学第一定律，并通过带电检验粒子与复标量场验证弱宇宙监督猜想，发现极端黑洞无法被摧毁，小NUT参数近极端黑洞可被带电粒子摧毁但不受复标量场影响。

Can test fields destroy the event horizon in the Kerr-Taub-NUT spacetime?

In this work we investigate if the interaction of the Kerr-Taub-NUT spacetime with test scalar and neutrino fields can lead to the destruction of the event horizon. It turns out that both extremal and nearly extremal black holes can be destroyed by scalar and neutrino fields if the initial angular momentum of the spacetime is sufficiently large relative to its mass and NUT charge. This is the first example in which a classical field satisfying the null energy condition can actually destroy an extremal black hole. For scalar fields, the modes that can lead to the destruction of the horizon are …

NUT-like and near-horizon limits of Kerr-NUT-(A)dS spacetimes

We study a class of limits of the higher-dimensional Kerr-NUT-(A)dS spacetimes where particular roots of metric functions degenerate. Namely, we obtain the Taub-NUT-(A)dS and the extreme near-horizon geometries as two examples of our limiting procedure. The symmetries of the resulting spacetimes are enhanced which is manifested by the presence of supplementary Killing vectors and decomposition of Killing tensors into Killing vectors.

广义加速Kerr-Newman-NUT-de Sitter黑洞

Generalized accelerating Kerr-Newman-NUT-de Sitter black holes

本文构造了带宇宙学常数的爱因斯坦-麦克斯韦方程的八参数旋转黑洞解，推广了加速Kerr-Newman-NUT-de Sitter时空，其中新参数$S_2$在静态极限下描述宇宙弦张力。

Separability of Hamilton-Jacobi and Klein-Gordon Equations in General Kerr-NUT-AdS Spacetimes

We demonstrate the separability of the Hamilton-Jacobi and scalar field equations in general higher dimensional Kerr-NUT-AdS spacetimes. No restriction on the parameters characterizing these metrics is imposed.

Dynamics and Fundamental Frequencies of Test Particles Orbiting Kerr-Newman-NUT-Kiselev Blacks Hole in Rastall Gravity

The spacetime properties in the exterior of the Kerr-Newman-NUT-Kiselev black hole in the Rastall theory of gravity, through particle dynamics are investigated with the aim to find possible degeneracy of the different black hole parameters. We show that the effective potential, the energy, and the angular momentum of a test particle moving in the spacetime of such a black hole strongly depend on the central black hole parameters. We also evaluate the innermost stable circular orbit radii of test particles and show how the spacetime parameters can act on them. Further, we show the results for t…

热NUT-Kerr-Newman-Kasuya-AdS时空的光学性质与热几何

Optical Properties and Thermal Geometries of Hot NUT-Kerr-Newman-Kasuya-AdS Spacetime

本文研究热NUT-Kerr-Newman-Kasuya-AdS黑洞的光学阴影与热几何，解析计算两类阴影图像并分析NUT荷、自旋、倾角及宇宙学常数的影响，发现Ruppeiner、HPEM和Quevedo(II)几何能揭示其微观结构。

Kerr-Schild Structure and Harmonic 2-forms on (A)dS-Kerr-NUT Metrics

We demonstrate that the general (A)dS-Kerr-NUT solutions in D dimensions with ([D/2], [(D+1)/2]) signature admit [D/2] linearly-independent, mutually-orthogonal and affinely-parameterised null geodesic congruences. This enables us to write the metrics in a multi-Kerr-Schild form, where the mass and all of the NUT parameters enter the metrics linearly. In the case of D=2n, we also obtain n harmonic 2-forms, which can be viewed as charged (A)dS-Kerr-NUT solution at the linear level of small-charge expansion, for the higher-dimensional Einstein-Maxwell theories. In the BPS limit, these 2-forms re…

通过磁重联从Kerr-Taub-NUT黑洞的俯仰区域提取能量

Extracting energy from plunging region of a Kerr-Taub-NUT black hole by magnetic reconnection

研究了通过磁重联从Kerr-Taub-NUT黑洞俯仰区域提取能量，发现引力磁荷抑制该过程，并利用该机制成功解释了GRS 1915+105的观测喷流功率和辐射效率。

Weak cosmic censorship conjecture for Kerr-Taub-NUT black hole with test scalar field and particle

Motivated by the recent researches of black holes with NUT charge, we investigate the validity of the weak cosmic censorship conjecture for Kerr-Taub-NUT black hole with a test massive scalar field and a test particle, respectively. For the scalar field scattering gedanken experiment, we consider an infinitesimal time interval process. The result shows that both extremal and near-extremal Kerr-Taub-NUT black holes cannot be over-spun. For the test particle thought experiment, the study suggests that extremal Kerr-Taub-NUT black hole cannot be over-spun; while near-extremal Kerr-Taub-NUT black …

On the parameters of the Kerr-NUT-(anti-)de Sitter space-time

Different forms of the metric for the Kerr-NUT-(anti-)de Sitter space-time are being widely used in its extension to higher dimensions. The purpose of this note is to relate the parameters that are being used to the physical parameters (mass, rotation, NUT and cosmological constant) in the basic four dimensional situation.

克尔 - 纽曼 - 纽特 - Λ时空的非线性电动力学：精确解、视界和能量条件

Nonlinear electrodynamics in Kerr-Newman-NUT-$Λ$ spacetime: exact solutions, horizons, and energy conditions

研究构建克尔 - 纽曼 - 纽特 - Λ时空的非线性电动力学推广，通过特定对齐简化麦克斯韦 - 法拉第部分，求解爱因斯坦方程得到度规等，分析能量条件等，发现非线性部分特性及奇点情况。

Deformed conformal symmetry of Kerr-Newman-NUT-AdS black holes

We find generators of the conformal symmetry for the class of Kerr-Newman-NUT-AdS black holes from the deformed scalar probe equation. We find two classes of solutions for the generators (also known as conformal J and Q pictures). The two classes of deformed generators are the extension of similar generators for the regular conformal symmetry. Moreover, we find that the two pictures can be generalized and extended into a general picture. In each picture, the generators produce an extended local family of SL(2,R)_L \times SL(2,R)_R hidden conformal symmetries for the Kerr-Newman-NUT-AdS black h…

Particle Acceleration on the Background of the Kerr-Taub-NUT Spacetime

We study the collision of two particles with the different rest masses moving in the equatorial plane of a Kerr-Taub-NUT spacetime and get the center-of-mass (CM) energy for the particles. We find that the CM energy depends not only on the rotation parameter, $a$, but also on the NUT charge of the Kerr-Taub-NUT spacetime, $n$. Especially, for the extremal Kerr-Taub-NUT spacetime, an unlimited CM energy can be approached if the parameter $a$ is in the range $[1,\sqrt{2}]$, which is different from that of the Kerr and Kerr-Newman black holes.

Hidden Symmetry of Higher Dimensional Kerr-NUT-AdS Spacetimes

It is well known that 4-dimensional Kerr-NUT-AdS spacetime possesses the hidden symmetry associated with the Killing-Yano tensor. This tensor is "universal" in the sense that there exist coordinates where it does not depend on any of the free parameters of the metric. Recently the general higher dimensional Kerr-NUT-AdS solutions of the Einstein equations were obtained. We demonstrate that all these metrics with arbitrary rotation and NUT parameters admit a universal Killing-Yano tensor. We give an explicit presentation of the Killing-Yano and Killing tensors and briefly discuss their properti…

Area Products and Mass Formula for Kerr-Newman-Taub-NUT Space-time

We derive area product, entropy product, area sum and entropy sum of the event horizon and Cauchy horizons for Kerr-Newman-Taub-NUT(Newman-Unti-Tamburino) black hole in four dimensional \emph{Lorentzian geometry}. We observe that these thermodynamic products are \emph{not} universal(mass-independence) for this black hole(BH), whereas for Kerr-Newman(KN) BH such products are universal (mass-independence). We also examine the entropy sum and area sum. It is shown that they all are depends on mass, charge and NUT parameter of the back ground space-time. Thus we can conclude that the universal(mas…

Kerr-de Sitter Black Holes with NUT Charges

The four-dimensional Kerr-de Sitter and Kerr-AdS black hole metrics have cohomogeneity 2, and they admit a generalisation in which an additional parameter characterising a NUT charge is included. In this paper, we study the higher-dimensional Kerr-AdS metrics, specialised to cohomogeneity 2 by appropriate restrictions on their rotation parameters, and we show how they too admit a generalisation in which an additional NUT-type parameter is introduced. We discuss also the supersymmetric limits of the new metrics. If one performs a Wick rotation to Euclidean spacetime signature, these yield new E…

Hawking Radiation via Tunneling from Hot NUT-Kerr-Newman-Kasuya Spacetime

We study the Hawking thermal spectrum in dragging coordinate system and the tunneling radiation characteristics of hot NUT-Kerr-Newman-Kasuya spacetime. The tunneling rates at the event and cosmological horizon are found to be related to the change of Bekenstein-Hawking entropy. The radiation spectrum is not pure thermal and thus there is a correction to the Hawking thermal spectrum.

薄盘流下Kerr-Taub-NUT黑洞的扩展内阴影

The extended inner shadow of Kerr-Taub-NUT black hole with thin disk flows

本文通过数值反向光线追踪研究Kerr-Taub-NUT黑洞薄盘图像，发现高自旋及特定NUT参数下内阴影出现超出临界曲线的“扩展内阴影”新结构，为检验NUT荷存在提供观测依据。

Kerr-Taub-NUT Spacetime with Maxwell and Dilaton Fields

We present an exact solution describing a stationary and axisymmetric object with electromagnetic and dilaton fields. The solution generalizes the usual Kerr-Taub-NUT (Newman-Unti-Tamburino) spacetime in general relativity and is obtained by boosting this spacetime in the fifth dimension and performing a Kaluza-Klein reduction to four dimensions. We also discuss the physical parameters of this solution and calculate its gyromagnetic ratio.

GUP对热NUT Kerr Newman Kasuya Anti de Sitter黑洞霍金温度的影响

GUP effects on Hawking temperature in a hot NUT Kerr Newman Kasuya Anti de Sitter black hole

本文研究了量子引力效应下热NUT Kerr Newman Kasuya Anti de Sitter黑洞霍金温度的修改及其稳定性影响。

Symmetry axes of Kerr-NUT-(A)dS spacetimes

We study fixed points of isometries of the higher-dimensional Kerr-NUT-(A)dS spacetimes that form generalizations of symmetry axes. It turns out that, in the presence of nonzero NUT charges, some parts of the symmetry axes are necessarily singular and their intersections are surrounded by regions with closed timelike curves. Motivated by similarities with the spacetime of a spinning cosmic string, we introduce geometric quantities that characterize various types of singularities on symmetry axes. Expanding the Kerr-NUT-(A)dS spacetimes around candidates for possible fixed points, we find the K…

Scalar and Spinor Perturbation to the Kerr-NUT Spacetime

We study the scalar and spinor perturbation, namely the Klein-Gordan and Dirac equations, in the Kerr-NUT space-time. The metric is invariant under the duality transformation involving the exchange of mass and NUT parameters on one hand and radial and angle coordinates on the other. We show that this invariance is also shared by the scalar and spinor perturbation equations. Further, by the duality transformation, one can go from the Kerr to the dual Kerr solution, and vice versa, and the same applies to the perturbation equations. In particular, it turns out that the potential barriers felt by…

Non-singular extension of the Kerr-NUT-(anti) de Sitter spacetimes

In 1963 Ezra Ted Newman and his two students Louis A. Tamburino, and Theodore W. J. Unti, proposed a deformation of the Shwarzschild spacetime that made it twisting. In the cosmological context, an equivalent solution had been found earlier, in 1951, by Abraham Haskel Taub. The problem that these solutions have is a conical singularity along the symmetry axis at all distances from the origin. In 1969 Misner proposed a non-singular interpretation of Taub-NUT spacetimes. We extend and refine his method to include a broader family of solutions and completely solve the outstanding issue of a non-s…

On hidden symmetries of extremal Kerr-NUT-AdS-dS black holes

It is well known that the Kerr-NUT-AdS-dS black hole admits two linearly independent Killing vectors and possesses a hidden symmetry generated by a rank-2 Killing tensor. The near-horizon geometry of an extremal Kerr-NUT-AdS-dS black hole admits four linearly independent Killing vectors, and we show how the hidden symmetry of the black hole itself is carried over by means of a modified Killing-Yano potential which is given explicitly. We demonstrate that the corresponding Killing tensor of the near-horizon geometry is reducible as it can be expressed in terms of the Casimir operators formed by…

Gravitomagnetism in the Kerr-Newman-Taub-NUT spacetime

We study the motion of test particles and electromagnetic waves in the Kerr-Newman-Taub-NUT spacetime in order to elucidate some of the effects associated with the gravitomagnetic monopole moment of the source. In particular, we determine in the linear approximation the contribution of this monopole to the gravitational time delay and the rotation of the plane of the polarization of electromagnetic waves. Moreover, we consider "spherical" orbits of uncharged test particles in the Kerr-Taub-NUT spacetime and discuss the modification of the Wilkins orbits due to the presence of the gravitomagnet…

从Taub-NUT瞬间子看Newman-Janis算法

Newman-Janis Algorithm from Taub-NUT Instantons

本文展示Kerr度规是自对偶与反自对偶Taub-NUT瞬间子的非线性叠加，推动Newman-Janis算法成为具有明确物理起源的Kerr度规推导方法。

Non-singular Kerr-NUT-de Sitter spacetimes

We study Killing horizons and their neighbourhoods in the Kerr-NUT-(anti-)de Sitter and the accelerated Kerr-NUT-(anti-)de Sitter spacetimes. The geometries of the horizons have an irremovable singularity at one of the poles, unless the parameters characterising the spacetimes satisfy the constraint we derive and solve in the current paper. In the Kerr-NUT-de Sitter case, the constraint relates the cosmological constant of spacetime and the horizon area, leaving 3 parameters free. In the accelerated case the acceleration becomes a 4th parameter that allows the cosmological constant to take arb…

Hidden conformal symmetry for Kerr-Newman-NUT-AdS black holes

We show the generic non-extremal Kerr-Newman-NUT-AdS black holes are holographically dual to the hidden conformal field theories in two different pictures. The two pictures can be merged together to the dual CFTs in general picture, that are generated by the $SL(2,\mathbb{Z})$ modular group. We also extend the calculation to the extremal limit and find the corresponding quantities. Using the extended central charges from the Kerr/CFT correspondence, we also find agreement between the macroscopic and microscopic entropies. We also find the absorption cross-section of the scalar probes for the g…

Duality and $μ$-separability of Maxwell equations in Kerr-NUT-(A)dS spacetime

We study properties of a recently proposed new ansatz for separation of variables in the Maxwell equations in four dimensional Kerr-NUT-(A)dS spacetime. We demonstrate that a dual field, which is also a solution of the source-free Maxwell equations, can be presented in a similar form. This result implies that the corresponding separated equations possess a discrete symmetry under a special transform of the separation parameters.

Amplitudes from Coulomb to Kerr-Taub-NUT

Electric-magnetic duality, the Newman-Janis shift, and the double copy all act by elementary operations on three-point amplitudes. At the same time, they generate a network of interesting classical solutions spanning from the Coulomb charge via the dyon to the Kerr-Taub-NUT spacetime. We identify the amplitudes corresponding to each of these solutions, working to all orders in spin, but to leading perturbative order. We confirm that the amplitudes double-copy when the solutions are related by the classical double copy. Along the way we show that the Kerr-Taub-NUT solution corresponds to a grav…