Vacuum polarization near the event horizon of a charged rotating black hole

1982 ◽  
Vol 26 (4) ◽  
pp. 954-955 ◽  
Author(s):  
V. P. Frolov
Keyword(s):  
Black Hole ◽  
Event Horizon ◽  
Vacuum Polarization ◽  
Rotating Black Hole

On embeddings of the Kerr geometry

1981 ◽  
Vol 59 (5) ◽  
pp. 688-692 ◽  
Author(s):  
Nigel A. Sharp
Keyword(s):  
Black Hole ◽  
Event Horizon ◽  
Equatorial Plane ◽  
Kerr Metric ◽  
Intrinsic Structure ◽  
Kerr Geometry ◽  
Rotating Black Hole ◽  
Isometric Embeddings

The use of isometric embeddings of curved geometries reveals their intrinsic structure in a way that is readily appreciated. This is done for 3 two-surfaces sliced from the Kerr metric which describes a rotating black hole: the equatorial plane, the event horizon, and the ergosurface.

Shadow from a rotating black hole in an extended gravity

2020 ◽  
Vol 35 (02n03) ◽  
pp. 2040060
Author(s):  
Vjacheslav Prokopov ◽  
Stanislav Alexeyev
Keyword(s):  
Black Hole ◽  
Event Horizon ◽  
Rotating Black Hole ◽  
Extended Gravity ◽  
Extended Theories Of Gravity ◽  
Theories Of Gravity ◽  
Extended Theories

We focus on the consequences of that the Event Horizon Telescope obtained images of the black hole shadow in the center of the M87 galaxy. We show that to test extended theories of gravity the improving of the resolution by 3 orders is necessary. In addition it is demonstrated that the rotation distorts the shape of the shadow and corrections from the extended gravity may affect on this distortion.

scholarly journals Quantum-Gravitational Trans-Planckian Energy of a Time-Dependent Black Hole

Symmetry ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1303
Author(s):  
A. J. Nurmagambetov ◽  
I. Y. Park
Keyword(s):  
Black Hole ◽  
Event Horizon ◽  
Black Hole Solution ◽  
Energy Analysis ◽  
Scaling Behavior ◽  
Time Dependent ◽  
Higgs Potential ◽  
Rotating Black Hole ◽  
Basic Features

We continue our recent endeavor in which a time-dependent black hole solution of a one-loop quantum-corrected Einstein-scalar system was obtained and its near-horizon behavior was analyzed. The energy analysis led to a trans-Planckian scaling behavior near the event horizon. In the present work, the analysis is extended to a rotating black hole solution of an Einstein–Maxwell-scalar system with a Higgs potential. Although the analysis becomes much more complex compared to that of the previous, we observe the same basic features, including the quantum-gravitational trans-Planckian energy near the horizon.

scholarly journals Estimate of the superradiance spectrum in dispersive media

2020 ◽  
Vol 378 (2177) ◽  
pp. 20190236 ◽  
Author(s):  
Theo Torres
Keyword(s):  
Black Hole ◽  
Reflection Coefficient ◽  
Event Horizon ◽  
Vortex Flow ◽  
Theoretical Description ◽  
Dispersive Media ◽  
Next Generation ◽  
Rotating Black Hole ◽  
Analogue Gravity ◽  
The Many

In 2016, the Nottingham group detected the rotational superradiance effect. While this experiment demonstrated the robustness of the superradiance process, it still lacks a complete theoretical description due to the many effects at stage in the experiment. In this paper, we shine new light on this experiment by deriving an estimate of the reflection coefficient in the dispersive regime by means of a Wentzel–Kramers–Brillouin analysis. This estimate is used to evaluate the reflection coefficient spectrum of counter-rotating modes in the Nottingham experiment. Our finding suggests that the vortex flow in the superradiance experiment was not purely absorbing, contrary to the event horizon of a rotating black hole. While this result increases the gap between this experimental vortex flow and a rotating black hole, it is argued that it is in fact this gap that is the source of novel ideas. This article is part of a discussion meeting issue ‘The next generation of analogue gravity experiments’.

scholarly journals Quantum-Gravitational Trans-Planckian Energy of a Time-Dependent Black Hole

2019 ◽  
Author(s):  
A. J. Nurmagambetov ◽  
I. Y. Park
Keyword(s):  
Black Hole ◽  
Event Horizon ◽  
Black Hole Solution ◽  
Energy Analysis ◽  
Scaling Behavior ◽  
Time Dependent ◽  
Higgs Potential ◽  
Rotating Black Hole ◽  
Basic Features

We continue our recent endeavor in which a time-dependent black hole solution of a one-loop quantum-corrected Einstein-scalar system was obtained and its near-horizon behavior was analyzed. The energy analysis led to a trans-Planckian scaling behavior near the event horizon. In the present work the analysis is extended to a rotating black hole solution of an Einstein-Maxwell-scalar system with a Higgs potential. Although the analysis becomes much more complex compared to that of the previous, we observe the same basic features, including the quantum-gravitational trans-Planckian energy near the horizon.

scholarly journals Constraining the tidal charge of brane black holes using their shadows

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
Juliano C. S. Neves
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Event Horizon ◽  
Upper Bound ◽  
Brane World ◽  
Nonlocal Effect ◽  
Rotating Black Hole

Abstract A constraint on the tidal charge generated within a brane world is shown. Using the shadow of a rotating black hole in a brane context in order to describe the M87* parameters recently announced by the Event Horizon Telescope Collaboration, the deviation from circularity of the reported shadow produces an upper bound on the bulk’s nonlocal effect, which is conceived of as a tidal charge in the four-dimensional brane induced by the five-dimensional bulk. Therefore, a deviation from circularity $$\lesssim 10\%$$≲10% leads to an upper bound on the tidal charge $$\lesssim 0.004M^2$$≲0.004M2.

scholarly journals Renormalized vacuum polarization of rotating black holes

2015 ◽  
Vol 24 (09) ◽  
pp. 1542007 ◽  
Author(s):  
Hugo R. C. Ferreira
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Vacuum Polarization ◽  
Kerr Black Hole ◽  
Quantum Field ◽  
Massive Scalar Field ◽  
Rotating Black Hole ◽  
Black Hole Spacetimes ◽  
Rotating Black Holes ◽  
General Method

Quantum field theory on rotating black hole spacetimes is plagued with technical difficulties. Here, we describe a general method to renormalize and compute the vacuum polarization of a quantum field in the Hartle–Hawking state on rotating black holes. We exemplify the technique with a massive scalar field on the warped AdS3 black hole solution to topologically massive gravity, a deformation of (2 + 1)-dimensional Einstein gravity. We use a "quasi-Euclidean" technique, which generalizes the Euclidean techniques used for static spacetimes, and we subtract the divergences by matching to a sum over mode solutions on Minkowski spacetime. This allows us, for the first time, to have a general method to compute the renormalized vacuum polarization, for a given quantum state, on a rotating black hole, such as the physically relevant case of the Kerr black hole in four dimensions.

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