scholarly journals Comments on “The Euclidean gravitational action as black hole entropy, singularities, and space-time voids” [J. Math. Phys. 49, 042501 (2008)]

2009 ◽  
Vol 50 (4) ◽  
pp. 042502 ◽  
Author(s):  
Abhas Mitra
Keyword(s):  
Black Hole ◽  
Black Hole Entropy ◽  
Space Time ◽  
Gravitational Action ◽  
Math Phys

Black Hole Entropy from Non-Commutative Geometry and Spontaneous Localisation

2019 ◽  
Author(s):  
Tejinder P. Singh ◽  
Palemkota Maithresh
Keyword(s):  
Black Hole ◽  
Black Hole Entropy ◽  
Entangled State ◽  
Schwarzschild Black Hole ◽  
Spectral Action ◽  
Black Hole Evaporation ◽  
Gravitational Action ◽  
Fluctuation Dissipation ◽  
Fluctuation Dissipation Theorem ◽  
Gravitational Entropy

In our recently proposed theory of quantum gravity, a black hole arises from the spontaneous localisation of an entangled state of a large number of atoms of space-time-matter [STM]. Prior to localisation, the non-commutative curvature of an STM atom is described by the spectral action of non-commutative geometry. By using the techniques of statistical thermodynamics from trace dynamics, we show that the gravitational entropy of a Schwarzschild black hole results from the microstates of the entangled STM atoms and is given (subject to certain assumptions) by the classical Euclidean gravitational action. This action, in turn, equals the Bekenstein-Hawking entropy (Area/$4{L_P}^2$) of the black hole. We argue that spontaneous localisation is related to black-hole evaporation through the fluctuation-dissipation theorem.

scholarly journals A NEW APPROACH TO BLACK HOLE MICROSTATES

1998 ◽  
Vol 13 (23) ◽  
pp. 1875-1879 ◽  
Author(s):  
RICHARD J. EPP ◽  
R. B. MANN
Keyword(s):  
Black Hole ◽  
Degrees Of Freedom ◽  
Black Hole Entropy ◽  
Space Time ◽  
Orthonormal Frame ◽  
Great Promise ◽  
Frame Field ◽  
New Approach ◽  
Four Dimensions ◽  
First Order

If one encodes the gravitational degrees of freedom in an orthonormal frame field, there is a very natural first-order action one can write down (which in four dimensions is known as the Goldberg action). In this letter we will show that this action contains a boundary action for certain microscopic degrees of freedom living at the horizon of a black hole, and argue that these degrees of freedom hold great promise for explaining the microstates responsible for black hole entropy, in any number of space–time dimensions. This approach faces many interesting challenges, both technical and conceptual.

scholarly journals Entropic gravity from noncommutative black holes

2017 ◽  
Vol 15 (01) ◽  
pp. 1850004 ◽  
Author(s):  
Rafael C. Nunes ◽  
Hooman Moradpour ◽  
Edésio M. Barboza ◽  
Everton M. C. Abreu ◽  
Jorge Ananias Neto
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Field ◽  
Cosmological Constant ◽  
Black Hole Entropy ◽  
Space Time ◽  
Isotropic Universe ◽  
Entropic Gravity ◽  
The Universe

In this paper, we investigated the effects of a noncommutative (NC) space-time on the dynamics of the Universe. We generalize the black hole entropy for a NC black hole. Then, using the entropic gravity formalism, we will show that the noncommutativity changes the strength of the gravitational field. By applying this result to a homogeneous and isotropic Universe containing nonrelativistic matter and a cosmological constant, we show that the modified scenario by the noncommutativity of the space-time is a better fit to the obtained data than the standard one at 68% CL.

scholarly journals Fermion Fields in BTZ Black Hole Space-Time and Entanglement Entropy

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Dharm Veer Singh ◽  
Sanjay Siwach
Keyword(s):  
Black Hole ◽  
Entanglement Entropy ◽  
Black Hole Entropy ◽  
Mass Term ◽  
Space Time ◽  
Btz Black Hole ◽  
Logarithmic Divergence ◽  
Fermion Fields ◽  
Leading Term ◽  
Area Law

We study the entanglement entropy of fermion fields in BTZ black hole space-time and calculate prefactor of the leading and subleading terms and logarithmic divergence term of the entropy using the discretized model. The leading term is the standard Bekenstein-Hawking area law and subleading term corresponds to first quantum corrections in black hole entropy. We also investigate the corrections to entanglement entropy for massive fermion fields in BTZ space-time. The mass term does not affect the area law.

Quantized Space-Time and Black Hole Entropy

2014 ◽  
Vol 83 (6) ◽  
pp. 064008 ◽  
Author(s):  
Meng-Sen Ma ◽  
Huai-Fan Li ◽  
Ren Zhao
Keyword(s):  
Black Hole ◽  
Black Hole Entropy ◽  
Space Time

A tale of two horizons

2015 ◽  
Vol 93 (9) ◽  
pp. 995-998 ◽  
Author(s):  
Sean Stotyn
Keyword(s):  
Black Hole ◽  
Black Hole Entropy ◽  
Space Time ◽  
Extremal Black Hole ◽  
Spherically Symmetric ◽  
De Sitter ◽  
Event Horizons ◽  
Extremal Limit ◽  
Horizon Geometry ◽  
Killing Horizons

I revisit the fate of coinciding horizons and the volume between them in the extremal limit of spherically symmetric black holes in four space–time dimensions, focusing on the Schwarzschild – de Sitter black hole for concreteness. The two Killing horizons in the limit space–time that are traditionally identified with the limiting event horizons of the non-extremal black hole are shown to instead be generated by an enhanced symmetry of the near horizon geometry (NHG). This dismantles the interpretation of the four-volume between the horizons remaining finite in the extremal limit. The NHG is reinterpreted as a tangent space–time to the degenerate black hole horizon, and geometrical objects, such as Killing vectors and Killing horizons, are carefully mapped between the bulk and the NHG. The implications for extremal black hole entropy are then discussed.

scholarly journals Reply to Pessoa, P.; Arderucio Costa, B., Comment on “Tsallis, C. Black Hole Entropy: A Closer Look. Entropy 2020, 22, 17”

Entropy ◽  
2021 ◽  
Vol 23 (5) ◽  
pp. 630
Author(s):  
Constantino Tsallis
Keyword(s):  
Black Hole ◽  
Black Hole Entropy ◽  
Recent Comment

In the present Reply we restrict our focus only onto the main erroneous claims by Pessoa and Costa in their recent Comment (Entropy 2020, 22, 1110).

scholarly journals Area Entropy and Quantized Mass of Black Holes from Information Theory

Entropy ◽  
2021 ◽  
Vol 23 (7) ◽  
pp. 858
Author(s):  
Dongshan He ◽  
Qingyu Cai
Keyword(s):  
Information Theory ◽  
Black Hole ◽  
Black Hole Entropy ◽  
Quantum Corrections ◽  
Compton Wavelength ◽  
Information Theoretic ◽  
Curved Space ◽  
Thermodynamic Entropy ◽  
Hole Area ◽  
The Relationship

In this paper, we present a derivation of the black hole area entropy with the relationship between entropy and information. The curved space of a black hole allows objects to be imaged in the same way as camera lenses. The maximal information that a black hole can gain is limited by both the Compton wavelength of the object and the diameter of the black hole. When an object falls into a black hole, its information disappears due to the no-hair theorem, and the entropy of the black hole increases correspondingly. The area entropy of a black hole can thus be obtained, which indicates that the Bekenstein–Hawking entropy is information entropy rather than thermodynamic entropy. The quantum corrections of black hole entropy are also obtained according to the limit of Compton wavelength of the captured particles, which makes the mass of a black hole naturally quantized. Our work provides an information-theoretic perspective for understanding the nature of black hole entropy.

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