All Questions
Tagged with black-holes thermodynamics
306
questions
3
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1
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96
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Different Bekenstein bound equations – what’s the difference?
Can someone help me understand the difference between the Beckenstein bound equations that I’ve come across? They all appear to have different dimensions.
I’ve been told that if you include the ...
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3
votes
0
answers
56
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Generalized entropy of black holes
In the review paper 2006.06872 by Maldacena, in eq.(2.4) they wrote that the total entropy of a black hole and its environment also has a contribution from the quantum fields outside the horizon which ...
- 404
0
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0
answers
91
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What are regular event horizons?
I am studying uniqueness theorems of Black Holes and I often see the word "regular event horizon" instead only event horizon. Many textbooks and literature do not define this term. Please ...
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1
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Trapping Hawking radiation in black holes?
I was reading this writing (https://davidwoolsey.com/AttO/AttO_blog/Entries/2020/7/13_Black_Holes_and_Transverse_Tidal_Effects%2C_a_revised_essay_on_some_thoughts.html) about considering tidal effects ...
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2
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0
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53
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Could supermassive black holes emit massive particles as part of the Hawking radiation (even if the probability is small)? [duplicate]
Supermassive black holes should have a very low Hawking temperature and therefore would emit very low energetic photons, only when the black hole has radiated most of its mass and becomes small it ...
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1
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0
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55
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Angular momentum, black holes and up-tunneling events in the vacuum
To give some context on the matter, I found these interesting articles (https://arxiv.org/abs/2007.11428 & https://arxiv.org/abs/2003.04927) where the authors analyzed, among other things, the ...
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9
votes
4
answers
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Is it possible to have a stable black hole that does not evaporate?
Black holes would presumably evaporate in the long future via Hawking radiation.
However is this inevitable? Or are there any mechanisms that would compensate the lost mass due to Hawking radiation ...
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0
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0
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21
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Is it correct to claim that Hawking-Page phase transition is related to the breaking point at the Page-time?
In the evaporation process of a Black Hole in an AdS space we have a Hawking-Page phase transition. We know that such a phase transition can be exhibited by a singular behavior. At the other hand, ...
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0
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0
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57
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Scattering approach for massless scalar Hawking radiation and Bogoliubov coefficients in Schwarzschild metric
Reflection coefficient from the scattering approach in tortoise coordinates, looks exactly like relationship between modulus squared of Bogoliubov coefficients. However I'm not able to figure out a ...
0
votes
1
answer
121
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Black hole information paradox
I read that it is generally believed that information is preserved in black hole evaporation, and people's views only diverge when it comes to how information is preserved. Is this true?
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1
answer
58
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Black Body Radiation similarity to Hawking Radiation
Do black body radiation of a 40-Earth mass osmium planet with radius of Earth which was just formed and has a temperature of 10000 degrees Celcius emit photons not just near it but even at infinity ...
- 1,534
0
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0
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45
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What is the difference between the cosmological and the black hole horizons in thermodynamics?
I want to know the different thermal behaviors between cosmological and black hole horizons, such as temperature, entropy and so on.
- 113
0
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0
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41
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Why are greybody factors necessary when dealing with Hawking radiation?
According to Wikipedia, greybody factors are corrections to the black hole Hawking radiation spectrum. They say that at the horizon the emission is that of a perfect black body, but the gravitational ...
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1
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0
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32
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How increase in area of the horizon implies that the horizon in spacelike using Raychaudhuri equation?
In a talk The enigma of black hole horizons, (at 24:37), it is said that
"Raychaudhuri equation implies, if the flux into H is positive, area increases and horizon is spacelike".
How ...
- 293
2
votes
0
answers
70
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Hawking radiation from photons?
I am reading a lot of papers that derive the Hawking temperature solving either the Klein Gordon equation for scalar fields or the Dirac equation for spin $\tfrac12$ particles via tunnelling ...
1
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0
answers
32
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Understanding Haywards trapping gravity
In the paper General Laws of Black hole Dynamics, Hayward has proposed a formula for trapping gravity of an outer trapping horizon given by
$\kappa$ = $\frac{1}{2}$ $\sqrt{-e^f \mathcal{L}_- \Theta_+}$...
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1
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0
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25
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Do all small-large AdS black hole phase transitions have swallow tail like behaviour for the Free Energy v/s Temperature plot?
In the literature the swallow tail like behaviour is prominently seen for small-large AdS black hole phase transition for the Free Energy vs Temperature Plot. Recently I was trying to reproduce the ...
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1
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0
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36
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Conformal mapping of Euclidean Schwarzschild AdS black hole
I have been trying to understand this for some time. given the Euclidean S-AdS black hole metric,
$$ ds^2 = f(r)d\tau^2 + \frac{1}{f(r)} dr^2 + r^2d\Omega^{2}_{D-2} $$
From what I understand this has ...
2
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0
answers
47
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Calculating the Bekenstein-Hawking entropy for 1+1 black hole with dilaton background
According to this paper the Bekenstein-Hawking entropy of a 1+1 black hole which described by the $SL_k(2,\mathbb{R})/U(1)$ WZW cigar geometry is given by the following formula appearing in eq. (5.7):
...
2
votes
0
answers
27
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Thermodynamics of supersymmetric black hole
For a 4-dimenstional supersymmetric Kerr Newman black hole, we have
$$\beta\Omega=2\pi i$$,
and the index
$$\text{Tr}[(-)^Fe^{-\beta(M-Q)}]=e^{S+\beta\Omega J}$$
with $S+\beta\Omega J$ being $\beta$ ...
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0
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0
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45
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The Calculation of the Volume of a Photon Sphere around a Black Hole
So, I chose this question for my chemistry assignment which is "How many moles of photons will it take to fill up the volume of the photon sphere around Sagittarius A". I realized there is ...
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2
votes
2
answers
129
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Is entropy dependent on mass alone?
The entropy of a non-rotating, non-charged black hole is only proportional to the surface area of its event horizon (Bekenstein, 1973).
The area of the event horizon of a spherical black hole is only ...
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2
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102
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Definitions of Thermodynamics and Holography
There are many differences between the laws of thermodynamics and the laws of black hole thermodynamics (BHT):
Zeroth Law: In thermodynamics, the Zeroth Law establishes the notion of thermal ...
user143181
3
votes
1
answer
151
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What size is the smallest black hole stable at Standard temperature & pressure?
I have seen several questions regarding the size of the absolute smallest black hole, the smallest stable black hole and similar. These made me wonder; what is the smallest stable black hole if it is ...
3
votes
0
answers
79
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Past null horizon
What are past null horizons and future null horizons? Are they the same as past event horizons and future event horizons? The literature on Black Holes often uses these terms but I don’t get it. ...
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2
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0
answers
69
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Relating phase transition with symmetry-breaking according to Landau Theory
I am trying to reproduce the results from this paper where they find out the expression for the Landau functional to be
$$\psi(x,t,p)=\frac{1}{4}(\frac{1}{x}+6x+px^3-4tx^2)$$
Now we plot Landau ...
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3
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0
answers
79
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Entanglement entropy as the source of Bekenstein-Hawking entropy
I think I'm missing something about interpreting a black hole's entanglement entropy as the source of it's Bekenstein-Hawking entropy, and I can't find any literature on it.
So, we know that our ...
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1
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1
answer
129
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Why is black hole mass proportional to the radius, whereas their entropy is proportional to their surface?
Both mass and entropy behave differently for black holes than for normal matter.
For simple Schwarzschild black holes, mass is proportional to their radius.
The Bekenstein-Hawing entropy is ...
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0
answers
54
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How does the lifetime and temperature of a black hole scale with mass in higher dimenstions?
I've tried to find out how the lifetime and temperature of a black hole scale with mass in a universe with more then 3 spatial dimensions. I've spent a while trying to look up an answer to this ...
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1
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1
answer
232
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Could any new structures be formed after the heat death of the universe?
When the universe would reach a maximal state of entropy, heat death would presumably be reached and no structures would be left after the last black hole would evaporate.
However, is this really true?...
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