Article
Physics, Particles & Fields
Brett McInnes
Summary: The Weak Gravity Conjecture suggests that extremal black holes must decay by emitting particles or smaller black holes, even if they are classical. However, the question of whether this process is compatible with the second law of thermodynamics remains unclear.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
Gourav Banerjee, Binata Panda
Summary: The study reviewed the field redefinition approach for determining Seeley-DeWitt coefficients and applied it to compute the first three coefficients for non-minimal N=1 Einstein-Maxwell supergravity. The third coefficient was used to calculate the logarithmic corrections for non-extremal black holes in the same supergravity theory.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
Tanay Kibe, Sukrut Mondkar, Ayan Mukhopadhyay, Hareram Swain
Summary: This study explores how the black hole complementarity principle can arise from quantum gravitational dynamics using a local semiclassical approximation. The findings suggest that the decoupling of different degrees of freedom is crucial for replicating infalling information without cloning it. The study also reveals that hair, which retains a residual time-dependent quantum state, can mirror infalling information after a decoupling time.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Physics, Particles & Fields
Biel Cardona, Pau Figueras
Summary: In this paper, lumpy black holes with AdSp x S-q asymptotics are studied, showing the geometry of the horizon near the merger and discussing the correlation between different families of black holes. The presence of non-trivial fluxes in the internal sphere is shown to affect the geometry and the behavior of the solutions.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
Stephen Angus, Kyoungho Cho, Kanghoon Lee
Summary: The study explores the classical double copy for ungauged half-maximal supergravities using Kaluza-Klein reduction of double field theory (DFT), finding a linear structure implying a classical double copy. The single copy is identified as a pair of Maxwell-scalar theories, which are obtained through KK reduction of a higher-dimensional single copy of DFT. The research also investigates T-duality transformations and applies the Buscher rule to obtain solutions with nontrivial fields.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
Marina David, Jun Nian
Summary: Researchers calculated the Bekenstein-Hawking entropy of near-extremal AdS(4) electrically charged rotating black holes using three different methods and found a unique and universal expression for the entropy and microstate counting via the AdS/CFT correspondence. They extended the Kerr/CFT correspondence to the near-extremal case, computed the left and right central charges, and utilized hidden conformal symmetry to calculate the Frolov-Thorne temperatures for the near-horizon geometry, providing a microscopic foundation for Hawking radiation.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
Donald Marolf, Jorge E. Santos
Summary: This study examines the stability of black hole saddles inside a spherical reflecting cavity, finding that coupled modes can be diagonalized in the Lichnerowicz operator to define a natural generalization of the pure-trace Wick-rotation recipe. This recipe reproduces the expected result from black hole thermodynamics, where large Euclidean black holes are stable saddles while small Euclidean black holes are unstable.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Particles & Fields
Antonio Amariti, Alessia Segati
Summary: The microstate counting of charged rotating AdS(5) supersymmetric black holes has been reformulated as an extremization problem based on the superconformal index of the corresponding 4d dual SCFT. This approach has been successfully applied to consistent truncations with known field theory dual descriptions. In this paper, the case of the Leigh-Strassler fixed point is studied, and agreement between the field theory and gravitational results is found.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Physics, Particles & Fields
Shanzhong Han
Summary: This study examines the Weyl double copy relation for vacuum solutions of the Einstein equations with a cosmological constant by treating the spin-1/2 massless free-field spinors as basic units. The findings demonstrate that the zeroth copy connects gravity fields and Dirac-Weyl fields, as well as the degenerate electromagnetic fields in curved spacetime. Furthermore, the study highlights the critical significance of the zeroth copy in time-dependent radiation solutions.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Particles & Fields
Daniel Harlow, Edgar Shaghoulian
Summary: This paper argues for a close connection between the absence of global symmetries in quantum gravity and a unitary solution to the black hole information problem. By analyzing recent calculations on evaporating black holes and discussing low-dimensional quantum gravity theories, the argument against global symmetries is extended to more realistic theories.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
Chen-Pin Yeh
Summary: This article uses holography to study real-time correlators for N = 4 super Yang Mills fields coupled to a pair of entangled quarks. By considering the acceleration of the two quarks, the connection with the ER=EPR conjecture is made.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Physics, Particles & Fields
Vaibhav Gautam, Masanori Hanada, Antal Jevicki, Cheng Peng
Summary: In gauge/gravity duality, matrix degrees of freedom on the gauge theory side are important for the emergent geometry. This paper discusses how entanglement on the gravity side can be described as entanglement between matrix degrees of freedom, which is different from the recently proposed target space entanglement. Our approach can play important roles in several classes of quantum states. Applications include defining spatial entanglement in a nonperturbative, regularized setup for fuzzy sphere and suggesting a gauge theory origin of the Page curve for a small black hole in AdS5xS5 that can evaporate without being attached to a heat bath.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Physics, Particles & Fields
Jeff Murugan, Jonathan P. Shock, Ruach Pillay Slayen
Summary: This study builds upon previous research on non-relativistic charged particles confined to a sphere enclosing a magnetic dipole, expanding the computations to include a relativistic spin-1/2 fermion and exploring the interpretation of the physics involved. In the strong-field/small-radius limit, the spectrum of the spin-1/2 Hamiltonian exhibits a Landau level structure similar to the spinless case, with the addition of a new zero-energy lowest Landau level. Additionally, level-crossings occur in the spectrum as the magnetic field strength increases, leading to wavefunctions localizing at the poles in the strong-field/small-radius limit.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
David S. Berman, Kwangeon Kim, Kanghoon Lee
Summary: Researchers have constructed the classical double copy formalism for M-theory, extending the current state of the art by including the three form potential of eleven dimensional supergravity along with the metric. The key to this extension is constructing a Kerr-Schild type Ansatz for exceptional field theory, which allows solutions of charged objects to be found from a set of single copy fields. The exceptional field theory formalism automatically produces the IIB Kerr-Schild ansatz, enabling the construction of the single copy for the fields of IIB supergravity with manifest SL(2) symmetry.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
Yan Liu, Hong-Da Lyu, Avinash Raju
Summary: The study focuses on the behavior of black hole singularities during the Hawking-Page phase transitions, finding that the Kasner exponents are continuous and nondifferentiable during second order phase transitions, but discontinuous during first order phase transitions. Arguments on the universality of this behavior are presented, along with discussions on possible observables in the dual field theory encoding the Kasner exponents.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Astronomy & Astrophysics
R. A. Konoplya, A. Zhidenko
Summary: The study reveals stable circular orbits in D-dimensional asymptotically anti-de Sitter black holes, unlike the flat case, indicating the presence of stable orbits for any higher curvature Lovelock corrections, with a universal scaling relationship with temperature.
CLASSICAL AND QUANTUM GRAVITY
(2021)
Article
Astronomy & Astrophysics
R. A. Konoplya
Summary: Recent research has found an exact solution describing a black hole immersed in a galactic-like distribution of matter. This study continues the analysis of the properties of this geometry through consideration of electromagnetic radiation. The influence of the environment on classical and quantum radiation around such black holes is estimated to be relatively small.
Article
Physics, Multidisciplinary
R. A. Konoplya, A. Zhidenko
Summary: Blazquez-Salcedo et al. obtained asymptotically flat traversable wormhole solutions in the Einstein-Dirac-Maxwell theory without phantom matter. The previously found solutions had issues, whereas the new solutions are asymmetric and endowed with smooth gravitational and matter fields, making them more realistic.
PHYSICAL REVIEW LETTERS
(2022)
Article
Astronomy & Astrophysics
R. A. Konoplya, A. Zhidenko
Summary: This study considers various profiles of matter distribution in galactic halos as the source term for the Einstein equations and finds exact solutions that represent the metric of a central black hole immersed in a galactic halo. Very accurate general analytical metrics, including all the particular models, are found in the astrophysically relevant regime.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
R. A. Konoplya
Summary: This article discusses the correspondence between quasinormal modes and parameters of circular null geodesics. The correspondence was initially proposed for gravitational and test field perturbations, but it was later found that it only holds for test fields and may be broken for gravitational and other non-minimally coupled fields. The article further specifies the correspondence and shows that even when it is guaranteed, it may not represent the full spectrum of quasinormal modes.
Article
Astronomy & Astrophysics
R. A. Konoplya
Summary: During the ringdown phase, the least damped quasinormal frequency dominates the gravitational signal emitted by a black hole. Modifications near the event horizon can impact the overtones, providing insights into the geometry of the event horizon. Overtones are stable against deformations of spacetime, distinguishing the event horizon from the surrounding environment. The larger energy contribution of overtones compared to echoes opens up new avenues for future observations.
INTERNATIONAL JOURNAL OF MODERN PHYSICS D
(2023)
Article
Astronomy & Astrophysics
R. A. Konoplya, Z. Stuchlik, A. Zhidenko, A. F. Zinhailo
Summary: We calculate the accurate quasinormal frequencies for a corrected quantum black hole using the coordinate-independent iterative procedure in the renormalization group theory, resulting in the Dymnikova regular black hole. We observe that the quantum correction has a minimal effect on the fundamental mode, but significantly impacts the overtones. This is due to the geometry deformation of the Schwarzschild black hole near the event horizon. In order to find precise values of overtones, we develop a general procedure to apply the Leaver method to metrics that are initially not expressed as rational functions.
Article
Astronomy & Astrophysics
R. A. Konoplya
Summary: The fundamental quasinormal modes of black holes in higher-derivative gravity are moderately corrected by the Weyl term. The first several overtones are highly sensitive to even a relatively small Weyl correction, which might be important when representing the earlier stage of the black hole ringdown. In addition, a problem related to the analytical parametrized approximation of the numerical black hole solution in the Einstein-Weyl theory has been solved by extending the parametrization of the metric to higher orders.
Article
Astronomy & Astrophysics
R. A. Konoplya, A. Zhidenko
Summary: We present an improved Mathematica code that uses the Bernstein spectral method to compute quasinormal frequencies for a general class of black holes. The code can handle asymptotically flat, de Sitter, or anti-de Sitter asymptotic. The method is particularly efficient in searching for purely imaginary and unstable modes, and we demonstrate its effectiveness in detecting the instability region of a charged scalar field in the background of a charged asymptotically de Sitter dilatonic black hole. We show that the instability has a superradiant nature and is significantly influenced by the dilaton field.
Article
Astronomy & Astrophysics
R. A. Konoplya, A. Zhidenko
Summary: This paper investigates the quasinormal spectrum of gravitational perturbations of Schwarzschild-de Sitter black holes and finds a new branch of purely imaginary modes. When the ratio of the event horizon radius to the cosmological horizon approaches zero, these quasinormal modes approach modes of empty de Sitter spacetime.
Article
Astronomy & Astrophysics
M. S. Churilova, R. A. Konoplya, A. Zhidenko
Summary: This article studies the quasinormal modes of fields in the extreme Schwarzschild-de Sitter background. It is found that perturbations of fermionic fields do not satisfy the Pöschl-Teller effective potential, but quasinormal modes are still obtained analytically using the Frobenius method. An analytical formula for the quasinormal frequencies of near-extreme Schwarzschild-de Sitter black holes is derived, which is valid for both bosonic and fermionic fields. The analysis is further extended to the case of charged rotating black holes, resulting in a general analytical formula for quasinormal modes of fields with different spins in the near extreme Kerr-Newman-de Sitter spacetime.
Article
Astronomy & Astrophysics
Kirill A. Bronnikov, Roman A. Konoplya, Thomas D. Pappas
Summary: The study presents a general parametrization method for describing spacetimes of spherically symmetric Lorentzian, traversable wormholes, with validity that extends beyond the weak field region. Experimental results show that the parametrization provides high accuracy at the first order in most cases.
Article
Astronomy & Astrophysics
R. A. Konoplya
Summary: The black hole solution in conformal Weyl gravity describes the evolution of gravitational field in different stages including Schwarzschild-like ringing, effective dark matter ringing, and de Sitter phase. The late-time behavior of the electromagnetic field is also different, as exponential tails appear even without the effective de Sitter term.
Article
Astronomy & Astrophysics
R. A. Konoplya, A. Zhidenko
Summary: The study explores asymptotically flat black holes in a general metric theory by constraining the metric class with additional symmetries, leading to the separation of variables in the Hamilton-Jacobi and Klein-Gordon equations. It is found that the black-hole shadow depends on a few deformation parameters if the metric functions change moderately near the black hole. Additionally, the shadow of a rotating black hole in the Einstein-dilaton-Gauss-Bonnet theory is well approximated when terms violating the separation of variables are neglected in the metric.
Article
Astronomy & Astrophysics
Roman A. Konoplya, Antonina F. Zinhailo