scholarly journals A novel notion of null infinity for c-boundaries and generalized black holes

2018 ◽  
Vol 2018 (9) ◽  
Author(s):  
I. P. Costa e Silva ◽  
J. L. Flores ◽  
J. Herrera
Keyword(s):  
Black Holes ◽  
Null Infinity

scholarly journals Horizon Hair of Extremal Black Holes and Measurements at Null Infinity

2018 ◽  
Vol 121 (13) ◽  
Author(s):  
Y. Angelopoulos ◽  
S. Aretakis ◽  
D. Gajic
Keyword(s):  
Black Holes ◽  
Null Infinity ◽  
Extremal Black Holes

scholarly journals On the Trapped Surface Characterization of Black Hole Region in Vaidya Spacetime

2018 ◽  
Vol 10 (1) ◽  
pp. 59
Author(s):  
Mohammed Kumah ◽  
Francis T. Oduro
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Event Horizon ◽  
Surface Characterization ◽  
Local Approach ◽  
Null Infinity ◽  
Trapped Surfaces ◽  
Marginally Trapped Surfaces ◽  
Trapped Surface

Characterizing black holes by means of classical event horizon is a global concept because it depends on future null infinity. This means, to find black hole region and event horizon requires the notion of the entire spacetime which is a teleological concept. With this as a motivation, we use local approach as a complementary means of characterizing black holes. In this paper we apply Gauss divergence and covariant divergence theorems to compute the fluxes and the divergences of the appropriate null vectors in Vaidya spacetime and thus explicitly determine the existence of trapped and marginally trapped surfaces in its black hole region.

scholarly journals Black-hole boundaries

2005 ◽  
Vol 83 (11) ◽  
pp. 1073-1099 ◽  
Author(s):  
Ivan Booth
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Recent Work ◽  
Numerical Relativity ◽  
Null Infinity ◽  
Event Horizons ◽  
Traditional Definition ◽  
Classical Black Holes ◽  
Definition Of ◽  
Future Null Infinity

Classical black holes and event horizons are highly nonlocal objects, defined in relation to the causal past of future null infinity. Alternative, quasilocal characterizations of black holes are often used in mathematical, quantum, and numerical relativity. These include apparent, Killing, trapping, isolated, dynamical, and slowly evolving horizons. All of these are closely associated with two-surfaces of zero outward null expansion. This paper reviews the traditional definition of black holes and provides an overview of some of the more recent work on alternative horizons.PACS Nos.: 04.20.Cv, 04.70.–s, 04.70.Bw

Hausdorff closed limits and the c -boundary II: null infinity and black holes

2019 ◽  
Vol 36 (18) ◽  
pp. 185007
Author(s):  
I P Costa e Silva ◽  
J L Flores ◽  
J Herrera
Keyword(s):  
Black Holes ◽  
Null Infinity

STRINGS FROM BLACK HOLES

1992 ◽  
Vol 01 (02) ◽  
pp. 355-361 ◽  
Author(s):  
ICHIRO ODA
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Event Horizon ◽  
Zero Mode ◽  
Center Of Mass ◽  
Two Dimensional ◽  
Null Infinity ◽  
Four Dimensions ◽  
Surface Fluctuation ◽  
Future Null Infinity

It is shown that surface fluctuation of the event horizon of black holes in four dimensions which have been previously studied by ’t Hooft can be understood in terms of the topological two-dimensional string. This interpretation is valid at the lowest order, with respect to the magnitude of the radial momentum per magnitude of the transverse momentum, when particles near the event horizon fall into the black hole and from which particles then emit to future null infinity, owing to the Hawking radiation. This implies that in such a kinematical regime only the zero mode, that is, the center-of-mass momentum of the Euclidean string, propagates on the surface of the event horizon.

scholarly journals Singularities, Black Holes, and Cosmic Censorship: A Tribute to Roger Penrose

2021 ◽  
Vol 51 (2) ◽  
Author(s):  
Klaas Landsman
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Cosmic Censorship ◽  
Early History ◽  
Singularity Theorem ◽  
Null Infinity ◽  
Strong Cosmic Censorship ◽  
History Of ◽  
Definition Of ◽  
Fundamental Tension

AbstractIn the light of his recent (and fully deserved) Nobel Prize, this pedagogical paper draws attention to a fundamental tension that drove Penrose’s work on general relativity. His 1965 singularity theorem (for which he got the prize) does not in fact imply the existence of black holes (even if its assumptions are met). Similarly, his versatile definition of a singular space–time does not match the generally accepted definition of a black hole (derived from his concept of null infinity). To overcome this, Penrose launched his cosmic censorship conjecture(s), whose evolution we discuss. In particular, we review both his own (mature) formulation and its later, inequivalent reformulation in the pde literature. As a compromise, one might say that in “generic” or “physically reasonable” space–times, weak cosmic censorship postulates the appearance and stability of event horizons, whereas strong cosmic censorship asks for the instability and ensuing disappearance of Cauchy horizons. As an encore, an “Appendix” by Erik Curiel reviews the early history of the definition of a black hole.

scholarly journals Bulk supertranslation memories: A concept reshaping the vacua and black holes of general relativity

2016 ◽  
Vol 25 (12) ◽  
pp. 1644006 ◽  
Author(s):  
Geoffrey Compère
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Memory Effect ◽  
Null Infinity ◽  
Asymptotically Flat ◽  
Fundamental Symmetry ◽  
Geometrical Features ◽  
Flat Spacetimes ◽  
Future Null Infinity

The memory effect is a prediction of general relativity on the same footing as the existence of gravitational waves. The memory effect is understood at future null infinity as a transition induced by null radiation from a Poincaré vacuum to another vacuum. Those are related by a supertranslation, which is a fundamental symmetry of asymptotically flat spacetimes. In this paper, I argue that finite supertranslation diffeomorphisms should be extended into the bulk spacetime consistently with canonical charge conservation. It then leads to fascinating geometrical features of gravitational Poincaré vacua. I then argue that in the process of black hole merger or gravitational collapse, dramatic but computable memory effects occur. They lead to a final stationary metric which qualitatively deviates from the Schwarzschild metric.

scholarly journals Post-Newtonian waveforms from spinning scattering amplitudes

2022 ◽  
Vol 2022 (1) ◽  
Author(s):  
Yilber Fabian Bautista ◽  
Nils Siemonsen
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Scattering Amplitudes ◽  
Radiation Field ◽  
Scattering Amplitude ◽  
Tree Level ◽  
Quadrupole Moments ◽  
Leading Order ◽  
Null Infinity ◽  
Binary Black Hole

Abstract We derive the classical gravitational radiation from an aligned spin binary black hole on closed orbits, using a dictionary built from the 5-point QFT scattering amplitude of two massive particles exchanging and emitting a graviton. We show explicitly the agreement of the transverse-traceless components of the radiative linear metric perturbations — and the corresponding gravitational wave energy flux — at future null infinity, derived from the scattering amplitude and those derived utilizing an effective worldline action in conjunction with multipolar post-Minkowskian matching. At the tree-level, this result holds at leading orders in the black holes’ velocities and up to quadratic order in their spins. At sub-leading order in black holes’ velocities, we demonstrate a matching of the radiation field for quasi-circular orbits in the no-spin limit. At the level of the radiation field, and to leading order in the velocities, there exists a one-to-one correspondence between the binary black hole mass and current quadrupole moments, and the scalar and linear-in-spin scattering amplitudes, respectively. Therefore, we show explicitly that waveforms, needed to detect gravitational waves from inspiraling binary black holes, can be derived consistently, to the orders considered, from the classical limit of quantum scattering amplitudes.

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