All Questions
Tagged with black-holes thermodynamics
97
questions with no upvoted or accepted answers
9
votes
3
answers
332
views
Quantum pressure and chemical potential for a Schwarzschild black hole?
Just as Hawking showed that even Schwarzschild black holes have a temperature, shouldn't they also have a pressure and chemical potential? Are there any analytical formulae of those as well as
$$ T_{...
- 6,611
7
votes
0
answers
291
views
Relation between maximally mixed state and thermal state
Hawking calculated the density matrix of the outgoing radiation to be a thermal state. I have heard people say this is a maximally mixed state. Is this because given a fixed average energy in the ...
- 71
7
votes
0
answers
715
views
The surface area to volume ratio of a sphere and the Bekenstein bound
I am trying to relate the surface-area-to-volume-ratio of a sphere to the Bekenstein bound. Since the surface-area-to-volume-ratio decreases with increasing volume, one would surmise that, per unit of ...
- 71
6
votes
0
answers
230
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Saddle point contributions to the gravitational path integral
In his lectures on black holes and quantum information, Tom Hartman states that the gravitational path integral can be approximated as
$$
Z(\beta) \approx \sum_{g_\text{cl}} e^{-I_E[g_\text{cl}, \phi]}...
- 141
4
votes
0
answers
147
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Can black holes prevent heat death?
I recently learnt that black holes possess among the highest amounts of entropy in the universe. I might have stretched the idea preposterously far, but is it possible that this might be one of the ...
- 1,764
4
votes
0
answers
107
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Merger of old black holes
On the eve of a possible announcement on the production of gravitational waves via a black hole merger, I think this question is quite aptly timed. I have a few questions regarding the evolution of ...
user106422
4
votes
0
answers
176
views
A problem with ADM mass in the derivation of 1st law of black hole thermodynamics
The definition of ADM mass is
$$M=\frac{1}{16\pi}\lim_{r\rightarrow\infty}\int \left(\frac{\partial h_{\mu\nu}}{\partial x^\mu}-\frac{\partial h_{\mu\mu}}{\partial x^\nu} \right)N^\nu dA$$
according ...
- 1,487
4
votes
0
answers
163
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Dimensional inconsistency in first law of black hole thermodynamics
The first law of black hole mechanics (let's simplify by considering a uncharged and non-rotating black hole) can be written as
$$\delta M = T \delta S$$
If I use the definition of Hawking ...
- 759
4
votes
2
answers
109
views
Do black hole horizons always increase?
In asymptotically flat spacetimes, the area of a black hole event horizon must always increase, provided the Null Convergence Condition is followed ($R_{\mu\nu}k^{\mu}k^{\nu}\geq0$ for all null ...
3
votes
0
answers
56
views
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
3
votes
0
answers
79
views
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. ...
- 59
3
votes
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 ...
- 31
3
votes
0
answers
54
views
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 ...
- 2,908
3
votes
0
answers
32
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Question on apparent super efficiency of the magnetic penrose process
Accordingly to this paper $[1]$, the efficiency of the so called Magnetic Penrose Process (MPP) is, for supermassive black holes of mass $M∼10^{10} M_{\odot}$ immersed in a magnetic field having $B∼10^...
- 3,085
3
votes
0
answers
83
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How quasinormal modes of black holes related to black hole temperature?
I have heard that quasinormal modes of black holes are related to black hole temperature. QNMs describe how a black hole reacts to perturbation. Forex, when a black hole is perturbed, it will emit ...
- 293