scholarly journals Testing horizon topology with electromagnetic observations

2020 ◽  
Vol 102 (10) ◽  
Author(s):  
Sourabh Nampalliwar ◽  
Arthur G. Suvorov ◽  
Kostas D. Kokkotas
Keyword(s):  
Horizon Topology

scholarly journals Nonlinear extensions of gravitating dyons: from NUT wormholes to Taub-Bolt instantons

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Daniel Flores-Alonso ◽  
Román Linares ◽  
Marco Maceda
Keyword(s):  
Phase Transition ◽  
Black Holes ◽  
Conformal Symmetry ◽  
Classical Approach ◽  
New Family ◽  
Traversable Wormholes ◽  
Magnetic Mass ◽  
Horizon Topology ◽  
Nonlinear Extensions ◽  
Recent Attention

Abstract Recent work has shown the existence of a unique nonlinear extension of electromagnetism which preserves conformal symmetry and allows for the freedom of duality rotations. Moreover, black holes and gravitational waves have been found to exist in this nonlinearly extended electrovacuum. We generalise these dyonic black holes in two major ways: with the relaxation of their horizon topology and with the inclusion of magnetic mass. Motivated by recent attention to traversable wormholes, we use this new family of Taub-NUT spaces to construct AdS wormholes. We explore some thermodynamic features by using a semi-classical approach. Our results show that a phase transition between the nut and bolt configurations arises in a similar way to the Maxwellian case.

Further selected solutions

2020 ◽  
pp. 200-258
Author(s):  
Piotr T. Chruściel
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
De Sitter ◽  
Stationary Black Hole ◽  
Static Vacuum ◽  
Black Hole Spacetimes ◽  
Wide Range ◽  
Dimensional Black Hole ◽  
Horizon Topology ◽  
Basic Features

In previous chapters we presented the key notions associated with stationary black-hole spacetimes, as well as the minimal set of metrics needed to illustrate the basic features of the world of black holes. In this chapter we present some further black holes, selected because of their physical and mathematical interest. We start, in Section 5.1, with the Kerr–de Sitter/anti-de Sitter metrics, the cosmological counterparts of the Kerr metrics. Section 5.2 contains a description of the Kerr–Newman–de Sitter/anti-de Sitter metrics, which are the charged relatives of the metrics presented in Section 5.1. In Section 5.3 we analyse in detail the global structure of the Emparan–Reall ‘black rings’: these are five-dimensional black-hole spacetimes with R × S 1 × S 2-horizon topology. The Rasheed metrics of Section 5.4 provide an example of black holes arising in Kaluza–Klein theories. The Birmingham family of metrics, presented in Section 5.5, forms the most general class known of explicit static vacuum metrics with cosmological constant in all dimensions, with a wide range of horizon topologies.

Black Ringoid in seven dimensions

2015 ◽  
Vol 24 (09) ◽  
pp. 1542019
Author(s):  
Burkhard Kleihaus ◽  
Jutta Kunz ◽  
Eugen Radu
Keyword(s):  
Event Horizon ◽  
Einstein Equations ◽  
Conical Singularities ◽  
Asymptotically Flat ◽  
Basic Properties ◽  
Black Rings ◽  
Angular Momenta ◽  
Higher Dimensional ◽  
Horizon Topology ◽  
Balanced Solutions

We discuss the basic properties of a class of static and spinning black ringoids (Br) in d = 7 spacetime dimensions. These asymptotically flat solutions of the vacuum Einstein equations possess an S2 × S3 event horizon topology. They are found for a specific metric ansatz and can be viewed as natural higher dimensional counterparts of the d = 5 black rings (BRs). Similar to that case, the static configurations are supported against collapse by conical singularities. We provide evidence for the existence of balanced solutions which are spinning and possess two equal magnitude angular momenta.

scholarly journals d⩾5 magnetized static, balanced black holes with S2×Sd−4 event horizon topology

2013 ◽  
Vol 723 (1-3) ◽  
pp. 182-189 ◽  
Author(s):  
Burkhard Kleihaus ◽  
Jutta Kunz ◽  
Eugen Radu
Keyword(s):  
Black Holes ◽  
Event Horizon ◽  
Horizon Topology

scholarly journals Pure Gauss–Bonnet NUT black hole with and without non-central singularity

2021 ◽  
Vol 81 (5) ◽  
Author(s):  
Sajal Mukherjee ◽  
Naresh Dadhich
Keyword(s):  
Black Hole ◽  
Event Horizon ◽  
Higher Dimensions ◽  
Radial Symmetry ◽  
Cosmological Horizon ◽  
Vacuum Equation ◽  
Closed Timelike Curves ◽  
Central Singularity ◽  
Horizon Topology ◽  
Nut Solution

AbstractIt is known that NUT solution has many interesting features and pathologies like being non-singular and having closed timelike curves. It turns out that in higher dimensions horizon topology cannot be spherical but it has instead to be product of 2-spheres so as to retain radial symmetry of spacetime. In this letter we wish to present a new solution of pure Gauss–Bonnet $$\Lambda $$ Λ -vacuum equation describing a black hole with NUT charge. It has three interesting cases: (a) black hole with both event and cosmological horizons with singularity being hidden behind the former, (b) a regular spacetime free of both horizon and singularity, and (c) black hole with event horizon without singularity and cosmological horizon. Singularity here is always non-centric at $$r \ne 0$$ r ≠ 0 .

UNCERTAINTY RELATION AND BLACK HOLE ENTROPY OF TOROIDAL SPACETIME

2004 ◽  
Vol 01 (06) ◽  
pp. 731-737
Author(s):  
SHUANG-QI HU ◽  
ZHAO REN
Keyword(s):  
Black Hole ◽  
Uncertainty Relation ◽  
Black Hole Entropy ◽  
State Density ◽  
Partition Functions ◽  
Brick Wall ◽  
Fermionic Field ◽  
Logarithmic Term ◽  
Horizon Topology ◽  
New Equation

By using the method of quantum statistics and via the new equation of state density motivated by the generalized uncertainty relation in the quantum gravity, we avoid the difficulty of solving wave equation, and directly derive the partition functions of bosonic and fermionic field in Toroidal black hole. Then we calculate the entropies of bosonic and fermionic field near the black hole horizon on the background of a black hole. In our result, the divergent logarithmic term and ultraviolet cutoff in the original brick-wall method by which the black hole entropy was derived no longer exist. It is shown that the entropy of the black hole is proportional to the area of the horizon. These results are similar to that in the black hole with horizon topology S2.

scholarly journals Anomalies, black strings and the charged Cardy formula

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Seyed Morteza Hosseini ◽  
Kiril Hristov ◽  
Yuji Tachikawa ◽  
Alberto Zaffaroni
Keyword(s):  
Black Holes ◽  
Riemann Surface ◽  
Two Dimensional ◽  
Dimensional Theory ◽  
Higher Dimensional ◽  
Rotating Black Holes ◽  
Black Strings ◽  
Horizon Topology ◽  
Electrically Charged ◽  
Cardy Formula

Abstract We derive the general anomaly polynomial for a class of two-dimensional CFTs arising as twisted compactifications of a higher-dimensional theory on compact manifolds ℳd, including the contribution of the isometries of ℳd. We then use the result to per- form a counting of microstates for electrically charged and rotating supersymmetric black strings in AdS5× S5 and AdS7× S4 with horizon topology BTZt⋉S2 and BTZt⋉S2×$$ {\Sigma}_{\mathfrak{g}} $$ Σ g , respectively, where $$ {\Sigma}_{\mathfrak{g}} $$ Σ g is a Riemann surface. We explicitly construct the latter class of solutions by uplifting a class of four-dimensional rotating black holes. We provide a microscopic explanation of the entropy of such black holes by using a charged version of the Cardy formula.

scholarly journals d⩾5 static black holes with S2×Sd−4 event horizon topology

2009 ◽  
Vol 678 (3) ◽  
pp. 301-307 ◽  
Author(s):  
Burkhard Kleihaus ◽  
Jutta Kunz ◽  
Eugen Radu
Keyword(s):  
Black Holes ◽  
Event Horizon ◽  
Horizon Topology
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