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HUP at an Event Horizon

  1. Dec 5, 2014 #1
    My question is: Is my picture of what happens as something approaches an event horizon accurate - and are there any citations describing it?

    I got my "picture" from a PBS broadcast several years ago. It was since mentioned in these forums, but I haven't been able to find an explicit mention of it in the literature accepted by this forum.

    The picture is this: First, an event horizon is dependent on a frame of reference. One object "Bob" can enter the event horizon of the reference frame of another object "Alice". I've seen what Bob sees described as "No Drama" - he simply sees his watch cross through some particular time, say noon, as he crosses the horizon.

    On the other hand, red shift and other effects prevent Alice from "seeing" much at all. But the events as described from her reference frame would be:
    1) Bob's watch never reaches noon and Bob never reaches the event horizon. In Alice's universe, Bob's time slows almost to a stop.
    2) Because of this "time freeze" and HUP, Bob's location cannot remain definite - and he begins to spread out over the event horizon.

    It's that last point that I'm having trouble with. When I try to find citable papers on how the issues resolved the bet (at least in the minds of Preskill and Hawkings), I find "Euclidean path integrals" with no mention of this "popular" explanation.

    Still, it makes sense that Bob cannot remain both stationary in time and fixed in space from Alice's reference frame. So I expect that Bob would take on an indefinite position - again, in Alice's reference frame.

    So what is the real scoop?
  2. jcsd
  3. Dec 5, 2014 #2

    Doug Huffman

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    Stanford U's Susskind on the development of the Holographic Principle 55 minutes.
  4. Dec 5, 2014 #3

    Doug Huffman

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    So, don't miss Susskinds jeremiad on erroneous take-aways from difficult analogies.
  5. Dec 5, 2014 #4
    From my work computer, I cannot view that video - but "thanks", I'm pretty sure what the content would be and I'll view it later.

    Is that a citable source according to these forum rules? I have two reasons for asking. First is that I replied to a post describing this effect and was told it was misinformation. Second, it seems to bear on the "firestorm" that is currently being described as occuring behind the event horizon - and I don't want to walk into that question without being sure on this point.
  6. Dec 5, 2014 #5
    I won't. Especially since I am tempted to make some potentially erroneous take-aways.
  7. Dec 5, 2014 #6
    That video made quick mention of Heisenberg Uncertainty Principle, but not at all in the way I had seen it presented before. In the earlier video, Alice had a chance to spread out. In this case, she simply fried. I think what happens is both.

    What was really interesting about the video was Suskind's terse description of how Alice's view of Alice compares to Bob's view of Alice. It is simply that both are views of the same event from different reference frames.

    This leads directly into my question about the black hole firewall - which I will post in another thread.
  8. Dec 5, 2014 #7


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    You are mixing quantum mechanics and gravity, which is something we don't know how to do.
  9. Dec 5, 2014 #8
    We'll have to struggle with it.
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