Article
Astronomy & Astrophysics
Brayden Hull, Robert B. Mann
Summary: In this study, the thermodynamics of a new class of asymptotically anti-de Sitter black holes with nonconstant curvature event horizons in Gauss-Bonnet Lovelock gravity are examined, with the cosmological constant acting as thermodynamic pressure. It is found that nontrivial curvature on the horizon can significantly affect their thermodynamic behavior, and novel triple points are observed in six dimensions between large and small uncharged black holes and thermal AdS. For charged black holes, a continuous set of triple points is found, with the range depending on the parameters in the horizon geometry. Additionally, new generalizations of massless and negative mass solutions previously observed in Einstein gravity are also identified.
Article
Astronomy & Astrophysics
Fabio M. Mele, Johannes Muench, Stratos Pateloudis
Summary: In this paper, the authors continue the analysis of the effective model of quantum Schwarzschild black holes. They find that the central singularity is resolved in the quantum-corrected spacetime and quantum effects become relevant at a mass-independent curvature scale. They focus on the thermodynamic properties of the effective polymer black hole and analyze the quantum corrections as functions of black and white hole masses. The study reveals an extremal minimal-sized configuration characterized by vanishing temperature and entropy. For large masses, the classical results are recovered and quantum corrections are negligible.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Physics, Multidisciplinary
Aditya Singh, Aritra Ghosh, Chandrasekhar Bhamidipati
Summary: In this paper, the effect of dark energy on the extended thermodynamic structure and interacting microstructures of black holes in AdS was studied through an analysis of thermodynamic geometry. It was found that dark energy significantly alters the dominant interactions of black hole microstructures, leading to long-ranged repulsive interactions. The Ruppeiner curvature scalar R in the entropy-pressure and temperature-volume planes revealed interesting patterns, especially in charged or rotating AdS black holes with quintessence.
FRONTIERS IN PHYSICS
(2021)
Article
Astronomy & Astrophysics
Li-Hua Wang, Meng-Sen Ma
Summary: This paper re-derives the black hole entropy of static spherically symmetric black holes based on the concept of fractal black hole horizon. The temperatures and heat capacities of Schwarzschild, Reissner-Nordstrom, and RN-AdS black holes are calculated, showing that these black holes are thermodynamically stable. The heat capacity of RN-AdS black hole exhibits Schottky anomaly-like behavior, indicating the existence of discrete energy levels and restricted microscopic degrees of freedom.
Article
Astronomy & Astrophysics
Yu-Peng Wang, Liang Ma, Yi Pang
Summary: We compute the Euclidean action of charged de Sitter black holes in the four-dimensional gravitational Euler-Heisenberg model, and find that it is controlled by the total entropy contributed by the black hole outer horizon and the cosmological horizon. The Euclidean action can be interpreted as the black hole production rate in de Sitter space for smooth configurations. We also observe that the 4-derivative couplings break the symmetry between the production rate of purely electric black holes and purely magnetic black holes, but electromagnetic duality induces a transformation on these couplings, mapping the physical quantities of one type of black hole to the other type while preserving the unitarity constraints.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Jitendra Kumar, Shafqat Ul Islam, Sushant G. Ghosh
Summary: In this study, a rotating black hole metric is constructed based on the research of LQG black holes, which exhibits rich spacetime structures and differs from Kerr black holes.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Alejandro Perez, Salvatore Ribisi, Sami Viollet
Summary: In this paper, a solvable toy model is constructed to describe the quantum dynamics of the interior of a spherical black hole with falling spherical scalar field excitations. The quantum gravity dynamics of realistic black holes emitting Hawking radiation is modeled using Kantowski-Sachs solutions with a massless scalar field when focusing on the deep interior region. The KS model becomes exactly solvable at both the classical and quantum levels in the suitable variables in the regime where r K M.
Article
Astronomy & Astrophysics
Naritaka Oshita, Niayesh Afshordi, Shinji Mukohyama
Summary: This study investigates the ringdown waveform and reflectivity of a Lifshitz scalar field around a fixed Schwarzschild black hole, finding that Lifshitz waves scattered by the black hole exhibit superradiance due to Lorentz breaking terms leading to superluminal propagation. This can allow Lifshitz waves to carry additional positive energy to infinity while leaving negative energy inside the Killing horizon, similar to the Penrose process in Kerr spacetime. The study also observes the emergence of long-lived quasinormal modes and drastic modifications to the greybody factor of a microscopic black hole with Hawking temperature comparable to the Lifshitz energy scale.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Physics, Multidisciplinary
Yong Xiao, Longting Zhang
Summary: The paper focuses on studying charged black hole solutions in the infinite derivative theory of gravity. By adding the electromagnetic field part to the effective action, the black hole solutions around the Reissner-Nordstrom metric are solved perturbatively and iteratively. The corresponding temperature, entropy, and electrostatic potential are calculated, and the first law of thermodynamics is verified.
COMMUNICATIONS IN THEORETICAL PHYSICS
(2022)
Article
Astronomy & Astrophysics
Sebastian Bahamonde, Ludovic Ducobu, Christian Pfeifer
Summary: Black holes play a crucial role in understanding gravitational interaction. Recent advancements in observation and detection have provided direct access to their properties and behavior, thus raising the demand for comparing models. This article investigates the existence of scalarized black holes in scalar-torsion theories of gravity and presents exact solutions for certain couplings and potential functions, as well as the possibility of establishing no-scalar-hair theorems.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
R. Casadio, R. da Rocha, P. Meert, L. Tabarroni, W. Barreto
Summary: Two types of information entropy in the quantum states of a black hole's matter core are studied. The quantum mechanical picture of a collapsing ball of dust in general relativity, including a non-trivial ground state and a spectrum of bound states, is described. Computed information entropies shed new light on the stability of the ground state and the spectrum of higher excited states.
CLASSICAL AND QUANTUM GRAVITY
(2023)
Article
Astronomy & Astrophysics
Roberto Casadio
Summary: Classical general relativity predicts the occurrence of spacetime singularities under very general conditions. However, from the perspective of the complete quantum theory of matter and gravity, it is argued that this scenario cannot be physically realized since no proper quantum state may contain the infinite momentum modes required to resolve the singularity.
Article
Astronomy & Astrophysics
Sina Kazemian, Mateo Pascual, Carlo Rovelli, Francesca Vidotto
Summary: The existence of an area gap as predicted by loop quantum gravity removes a main objection to the scenario where a black hole may leave a remnant with a large amount of stored information at the end of its evaporation. We have modeled the emission from these remnants and derived properties of the diffuse radiation emitted by a population of such objects. By measuring the frequency and energy density of this radiation, it is possible to estimate the mass of the parent black holes and the remnant density, if the age of the population is known.
CLASSICAL AND QUANTUM GRAVITY
(2023)
Article
Astronomy & Astrophysics
Astrid Eichhorn, Aaron Held
Summary: This paper investigates the true nature of black holes by constructing regular black-hole spacetimes based on new-physics models, characterizing them by curvature invariants, and analyzing features such as the shadow shape and photon rings. Simulated images of the regular spinning black hole are generated to test the visibility of characteristic features in the intensity map, providing insights into the new-physics effects.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Physics, Multidisciplinary
J. R. M. de Nova, P. F. Palacios, I Carusotto, F. Sols
Summary: This study examines the instability spectrum and time evolution of a flowing quantum gas in a black-hole laser configuration, providing a theoretical tool for identification of black-hole lasing in future experiments. The research confirms the presence of a well-defined phase diagram at long times, indicating universality in the long-time behavior of a black-hole laser.
NEW JOURNAL OF PHYSICS
(2021)
Article
Astronomy & Astrophysics
Clifford Johnson
MODERN PHYSICS LETTERS A
(2018)
Article
Astronomy & Astrophysics
Clifford Johnson, Felipe Rosso
CLASSICAL AND QUANTUM GRAVITY
(2019)
Article
Astronomy & Astrophysics
Clifford V. Johnson
INTERNATIONAL JOURNAL OF MODERN PHYSICS D
(2019)
Article
Astronomy & Astrophysics
Clifford Johnson
CLASSICAL AND QUANTUM GRAVITY
(2020)
Article
Astronomy & Astrophysics
Clifford V. Johnson
CLASSICAL AND QUANTUM GRAVITY
(2020)
Article
Astronomy & Astrophysics
Clifford Johnson
MODERN PHYSICS LETTERS A
(2020)
Article
Physics, Multidisciplinary
Clifford V. Johnson
Summary: Various two dimensional quantum gravity theories of Jackiw-Teitelboim (JT) form can be described as random matrix models, providing explicit descriptions of microstate degrees of freedom. By using a Fredholm determinant det(1-K), the statistics of energy levels and quenched free energy F-Q (T) of the system can be computed. These results are also relevant to quantum properties of black holes in higher dimensions.
PHYSICAL REVIEW LETTERS
(2021)
Article
Astronomy & Astrophysics
Clifford Johnson
Summary: Recent work has shown that random matrix models have become a powerful tool in the study of Euclidean quantum gravity, black hole thermodynamics, and the holographic principle. These models allow for the investigation of physics beyond perturbative expansion and provide insights into the underlying microstates of quantum gravity, with applications in the low-temperature dynamics of various black holes.
INTERNATIONAL JOURNAL OF MODERN PHYSICS D
(2022)
Article
Astronomy & Astrophysics
Clifford Johnson, Felipe Rosso, Andrew Svesko
Summary: The study focuses on a JT supergravity theory and demonstrates its connection to certain matrix models, offering a nonperturbative computation method. The theory is considered a combination of specific type 0B minimal string theories, and it is suggested that other JT supergravities may also be defined similarly.
Article
Astronomy & Astrophysics
Clifford Johnson
Summary: The proposed construction provides a complete definition for the family of Jackiw-Teitelboim supergravities, connecting to matrix models, using a combination of minimal string theories. This nonperturbative physics construction is stable and well-defined, revealing special properties for half-integer Gamma values in the supergravity models.
Article
Astronomy & Astrophysics
Clifford Johnson
Summary: This article explores recently proposed definitions of JT gravity and supergravities, based on combinations of minimal string models, focusing on physics beyond perturbative expansion in spacetime topology. By using a combination of analytical and numerical methods, physics can be extracted with high accuracy in a simple controlled truncation scheme. Nonperturbative spectral densities are explicitly computed and displayed, including important contributions from wormhole geometries.
Article
Astronomy & Astrophysics
Clifford Johnson
Article
Astronomy & Astrophysics
Clifford Johnson, Victoria L. Martin, Andrew Svesko
Article
Astronomy & Astrophysics
Clifford Johnson
