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Questions tagged [hawking-radiation]

Radiation seen by static observers due to quantum effects in close vicinity to a black hole, leading to the potential for eventual evaporation of black holes. Pictorially, a particle-antiparticle pair is created, with one falling through the horizon, becoming causally lost to the rest of the universe, while its neighbor escapes the gravitational potential. Originally predicted by S. Hawking in the 1970s using quantum field theory in curved spacetime.

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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 ...
mathemania's user avatar
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Do black holes evaporate prior to crossing their event horizon? [duplicate]

Bob falls into a black hole, watched by Alice who is far away. Alice sees Bob asymptotically approach the event horizon while his clock asymptotically approaches 12:00 noon as his image redshifts (...
Matt's user avatar
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Probability of a primordial black hole absorbing background radiation?

I'm thinking of the early universe when there was a lot of energetic radiation around. A primordial black hole (PBH) that would be about to evaporate completely about now, would have an initial mass ...
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Does the positive energy particle emitted from Hawking radiation directly equate to the amount of mass contained within the black hole?

With virtual particle-antiparticle pairs in Hawking radiation, one member of the pair falls into the black hole, typically with negative energy, while the other escapes, typically with positive energy....
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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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Hawking-like radiation will probably be difficult to detect (even if it can be detected). Why is that?

I was having a conversation in another physics forum about horizons (like the event horizon of a black hole, or a cosmological horizon) emitting Hawking radiation and I mentioned that if the universe ...
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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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How to relate the two expressions of thermal spectrum?

I am reading a proof of the fact that if there exists a monochromatic plane electromagnetic wave for an observer in frame $S$, an observer in a frame $S'$, which is uniformly accelerated with respect ...
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Can black holes exchange Hawking radiation, avoiding complete evaporation?

I was wondering if it would be possible that, as a black hole radiates its mass as Hawking radiation, another black hole could absorb that radiation and then when the second black hole radiates its ...
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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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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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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 ...
Sachin Vaidya's user avatar
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On entropy in a de Sitter horizon in a universe undergoing accelerated expansion?

I have a question about de Sitter cosmological horizons: In this video by Leonard Susskind (https://youtu.be/n7eW-xPEvoQ?t=2324) he explains the concept of the Poincaré recurrence using particles and ...
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Hawking Radiation paradox

How does Hawking radiation help in information conservation? Doesn't it create a paradox, as the particle-antiparticle pair created at the event horizon has nothing to do with the matter that has ...
Bhavya Panda's user avatar
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Gray body factors of PBH's - radial equation approximation (Page 1976)

I'm deriving the results of the Page paper: "Particle emission rates from a black hole: Massless particles from an uncharged, nonrotating hole*" (https://doi.org/10.1103/PhysRevD.13.198). At ...
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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 ...
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Does matter in the outside universe affect Hawking radiation? [closed]

Is there a way to modify the event horizon to make it generate other particles by affecting quantum fields outside with a giant charge increasing quantum foam disruptions affecting the radiation? Is ...
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Don't all objects that collapse have an apparent event horizon and so Hawking radiates?

So say there is an object that is in the form of gas and dust and a core that weighs 10 earths is in the center and there is a sphere of gas around it that weighs 50 Earths, so the final mass is only ...
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The Formula For Entanglement Entropy of an Evaporating Black Hole

I am trying to find a proof for the formula for entanglement entropy of an evaporating Black Hole. It is introduced and used in many papers such as The entropy of Hawking radiation, by Ahmed Almheiri, ...
TheFyziker's user avatar
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Hawking radiation: what does a new external particle have to do with the mass of the black hole?

This question has been asked a few times here in a few different ways but the answers don't quite seem to land for me. Considering the virtual particle pair; one falls in, one escapes, both become ...
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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 ...
Níckolas Alves's user avatar
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About the geometric optics approximation in Hawking radiation

I have read Hawking's famous paper Particle creation by Black Holes (Ref. 1) and I have some doubts about the geometric optics approximation and its implications in the argument being made. The ...
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If Hawking radiation is observer dependent then is the mass of a black hole too?

I have read this question (in the comments): Late response, but the energy really comes from the gravitational field, which exists outside the event horiz0n and in space. This field is what lets us ...
Árpád Szendrei's user avatar
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Does Hawking radiation depend of what's inside a black hole?

Or is it entirely based on the existence of an event horizon? Does the fact that black holes radiate depend on any properties of its interior?
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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 ...
Nicola Muttoni's user avatar
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(Why) does the late radiation after page time entangle with the early radiation?

In Jerusalem lectures by Harlow Pg. 53 it is said that At the beginning of the evaporation process the radiation that comes out is entangled with the remaining black hole. But eventually it must ...
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Minimal mass of (Schwarzchild) black hole [duplicate]

After interesting presentation at academic days of emeritus professor of the University of Ljubljana (UL) Andrej Čadež about a notion and detecting of gravitational waves in 2016 an answer arose >...
Jani Melik's user avatar
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Is some form of Hawking radiation required to explain the universe we see?

If there were no Hawking radiation (and no black hole radiation of any kind, or any way for black holes to reduce in size or disappear), then it seems a black hole would represent an irreversible end ...
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Hawking Radiation: Mass implications on black holes [duplicate]

Empty space, is indeed not 'empty.' It is filled with the formation of particle-antiparticle pairs due to Heisenberg uncertainty. Now one of these particles escape into infinity but one of these ...
Rishabh Pal's user avatar
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Cosmological horizon and Hawking/Unruh radiation? [closed]

I have two questions about cosmological horizons and their emission of radiation The first one is: There are some authors that propose that dark energy or the accelerated expansion of the universe ...
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Hawking radiation reduces mass of Black Hole?

If hawking radiation is the result of a pair of virtual particles popping into existence just outside the event horizon, and then one falling into the black hole through the event horizon, and the ...
Charles Bretana's user avatar
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2 answers
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Why is Unruh radiation in a full 4$\pi$ solid angle contrary to Hawking's radiation?

I have some trouble asking this question, so I will try a roundabout approach to explain what I mean. If (outside of Earth atmosphere) one looks at the sun from different distances, the light coming ...
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Why negative energy particles not created near a black hole? [duplicate]

If you take empty space right next to a black hole once in awhile, you will get a positive particle being admitted in the opposite direction of the black hole. In the creation of the photon this ...
Christopher Cuddy's user avatar
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Why do we expect unitarity to be preserved in the black hole information paradox?

Consider the following way of describing the black hole information paradox: Suppose we start with a pure quantum state and a black hole of mass $M$. Now we throw the pure state into the black hole ...
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Can an entity trapped past the event horizon detect getting turned into Hawking radiation?

Assuming your space ship survives engaging with the accretion disk and any spaghettification issues: (1) I’ve read that the crew can’t tell if they’ve already crossed the event horizon. There wouldn’t ...
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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 ...
Infinite_Maelstrom's user avatar
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Can, in theory, information escape an event horizon via a specialized setup?

Can, in theory, information escape an event horizon via a specialized setup? Specifically, send a beam of photons to be barely—just barely—inside the event horizon, then wait for hawking radiation to ...
Lukephil Brecht's user avatar
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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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DeSitter cosmological horizon stability?

If the universe keeps expanding at an accelerated rate (given by the cosmological constant) then the universe would approach a DeSitter spacetime where there would be a cosmological horizon that would ...
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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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Would this experiment potentially work for detecting whether gravitons exist?

Take a primordial black hole and measure the Hawking radiation over a large amount of time by gamma-ray detectors, as well as a Large neutrino detector. Using theoretical calculations about the ...
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Can we infer Hawking radiation assuming the Unruh effect?

An observer near the event horizon of a black hole will experience an extremely strong gravitational field. Due to the principle of equivalence, this observer cannot locally distinguish between this ...
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What would Hawking radiation look like from inside the event horizon?

Let’s say you fell into a rotating black hole, the inner horizon of the black hole is an infinite blue shift surface, so you should be able to observe events from the arbitrarily far future before ...
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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?...
vengaq's user avatar
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Could the observed GZK limit exceeding cosmic rays be due to hawking radiation?

In this question here, it was asked whether a black hole could emit protons with energies exceeding the GZK limit via Hawking radiation, the answer given was yes. So I ask, what proportion if observed ...
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Do evaporating black holes emit gravitons? [duplicate]

Do evaporating black holes emit gravitons? I know that hawking radiation consists of photons, and that for very small black holes it can also consists of sun atomic particles, but what about gravitons?...
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How exactly does Hawking radiation occur? [duplicate]

I understand some parts of the theory, I've read from here https://phys.libretexts.org/Bookshelves/Astronomy__Cosmology/Supplemental_Modules_(Astronomy_and_Cosmology)/Cosmology/Carlip/...
Leon Raj's user avatar
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Hairy black hole

I was wondering why it is said that if a black hole has hair we can measure its charge at infinity, where does this statement come from? It doesn't seem right to me because solutions to KG equation ...
TTT's user avatar
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How close would a evaporating primodial black hole be to be detected? [closed]

The power output of a black holes hawking radiation is inversely proportional to the square of it's mass. According to here, in it's final second of existence, it'll emit over 2E22 joules of energy, ...
blademan9999's user avatar
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A question about Kerr black holes and Hawking radiation

It's a common myth that somoene falling into a black hole will see the entire history of the universe before they cross the event horizon. With a Kerr black hole however, it's sort of true. The inner ...
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