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A I am looking for information on holographic cosmology -- information falling into a BH

  1. May 29, 2017 #1
    When they talk about information falling into a black hole, are they referring to the basic defining parameters of the particles falling into the hole?
  2. jcsd
  3. May 29, 2017 #2


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    Their speed, momenta, and any other quantities.

    One way to think of it is this: if you have a black hole, and know its state perfectly, could you determine precisely all of the matter that had fallen into it?

    It goes towards the heart of physics, because General Relativity says that the information is destroyed, that there's no property of the black hole that is in any way dependent upon the precise details of the matter that fell into it. A black hole, in General Relativity, has angular momentum, mass, and charge as properties and that's it.

    But quantum mechanics, as far as we know, has a property called unitarity: if I know the exact state of the system at time T, then I can, given enough computer power, calculate the precise state of the system at any other time, no matter what.

    Since we don't know the precise quantum description of a black hole, we can't say for sure whether or not information is conserved, or what state it's in if it is conserved.
  4. May 29, 2017 #3
    So the surface area of the event horizon is related to the amount of information that been accumulated by the black hole. I think we are looking at some sort of Planck scale unit of area here. Perhaps a tessellation of triangles each a Planck length on a side. Each unit area hold a bit of information? So if an elementary particle can be defined by say five bits of information, then for each particle that falls in, five unit areas area added to the area of the event horizon? Would those bits of information be contiguous? If not, how would then be correlated? When Hawking radiation carries information away from the black hole, is that information going out in sets that relate to each particle that fell in, or is there just some sort of random mixing of bits from multiple particles?
  5. May 29, 2017 #4


    Staff: Mentor

    They are referring to information about the state of the particles falling into the hole.

    This seems to be the standard expectation of what we will find when we have a theory of quantum gravity. But at this point we don't know.

    Same comment as above.

    For the rest of your post, you might try looking up sources on the black hole information paradox.
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