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Semiclassical Black Hole

  1. Feb 11, 2015 #1


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    Hello. I'm thinking about Hawking radation and there's one thing I find a bit strange. The radiation is usually described as originating at he even horizon. The explanation makes sense and all, but still how can this locally non-special place become the seat of a local phenomenon(emitting Hawking radiation) ?
    So my question is : is it possible to interpret it diferently ? Could it possibly be described as particules tunelling from the singularity/quantum region into outer space (outside the event horizon) ? I guess this could be easy to rule out, maybe the decay of his tunelling with radius is all wrong... ? So does this make any kind of sense ?
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  3. Feb 11, 2015 #2


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    Hawking radiation is not emitted from the EH, it is a result of (simplistic description) virtual particles popping into existence just outside the EH and one of them crossing over and not being able to get back, so the other just wanders away.

    Hawking himself has said that this whole "virtual particle" description of the radiation is an analogy, not a statement of fact. It is the only way he could think of to translate the math of what's actually happening into understandable English.
  4. Feb 11, 2015 #3


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    Thanks, this makes sense. However, an alternative interpretation might be equally valid if it matches the calculation. I have no valid reason to think tunelling might be one, but I'd be interested to know if it's been studied...
  5. Feb 14, 2015 #4
    Yes, there is a model in which one component is the pair production which happens behind the horizon with the positive energy particle tunnelling out:
  6. Feb 14, 2015 #5


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    Maybe this pedagogic paper helps:


    It discusses the notion of "particle" in QFT in chapter 9, and the relation with the Unruh effect and Hawking radiation in section 9.6. I found it very useful.
  7. Feb 14, 2015 #6


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    Thanks everyone for taking the time to respond.

    It does! Also saved it for future reference.

    Interesting. Tunnelling happens at the horizon so it looks related to the usual description.
    I now think what I had in mind is most likely meaningless: I was talking about tunneling particles from the singularity to the horizon which, aside from the large macroscopic distance, seems to be like using "a perturbative expansion around a singularity".. Not so promising.
  8. Feb 14, 2015 #7


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    An explicitly local description of particle creation by gravitational backgrounds (including those of black holes) is presented in
    It is shown that particle creation only happens at positions where metric is time dependent, and explained why in the case of Hawking radiation this means - near the horizon.
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