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Quantum bounce

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  1. Aug 9, 2014 #1
    Does quantum bounce provide a solution by which black holes could on some other side of the universe or in another universe create white holes



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  3. Aug 9, 2014 #2

    mfb

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    What do you mean with "some other side of the universe"?

    No.
     
  4. Aug 9, 2014 #3
    Well I meant create an opening in space time elsewhere in our universe or in another universe via multiverse model


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  5. Aug 9, 2014 #4
  6. Aug 9, 2014 #5

    marcus

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    Yes! Fascinating paper. Thanks for reminding us of it. I worked through their math to get an estimate of which primordial black holes would be exploding at the current time (if they are right.)

    This involves choosing values (which they suggest as reasonable) for some parameters which they left variable.

    I'll go back and look at my notes. As I recall the initial mass of the black hole had to be something like 1020 kilograms in order for it not to have exploded already. Maybe more. I'll check and get back to you.
     
  7. Aug 9, 2014 #6

    marcus

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    Before I go check, there's an interesting feature we should be clear about. Let's focus on just this paper! (Other people have talked about BH to WH tunneling to somewhere else in the universe or to a "different universe". That talk comes up sporadically and has been going on for decades.)

    What Haggard and Rovelli are talking about is simpler and more direct: the physical explosion of a black hole in situ, right where it formed in the first place. No "wormhole" no "multiverse", just a bounce---involving a transition from a collapsing to an expanding state which (although unlikely in the short run to occur) they calculate must eventually occur after a sufficiently long time.
     
  8. Aug 9, 2014 #7

    marcus

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    Jim, did you happen to see last month's account of the discussion around this paper in Nature News?

    You can get it simply by googling "black holes explode" and it is the first hit.
    http://www.nature.com/news/quantum-bounce-could-make-black-holes-explode-1.15573

    It's better than a lot of other science journalism, by Ron Cowen. He gets comment from four other prominent physicists involved with quantum gravity and black holes:
    Abhay Ashtekar (the grand old man of that branch of research) at Penn State, and three Santa Barbara people: Steve Giddings, Don Marolf, and Joe Polchinski.

    They help to give the necessary context and cautiousness, which must accompany any new idea.

    The new idea is interesting because of its simplicity and because it does away with paradoxes and seeming contradictions that have arisen over the years around the original Hawking idea of BHs gradually evaporating thermally (typically over the course of trillions of years, or longer). Ron Cowen is a pretty good journalist and he explained that pretty well as I recall, so I won't take time to explain it.

    Haggard Rovelli's idea in a sense "cuts a Gordian knot". BHs don't have paradoxes or do anything really weird like sneaking out the back door into a different universe, they simply explode after a sufficiently long time, making something that looks like the gamma ray bursts (GRB) that are sometimes seen. GRB come in a range of sizes and a range of mechanisms have been proposed (just like there are various mechanisms for supernovas). BH explosion (a la Haggard Rovelli) would be a mechanism to explain the smaller type of GRB.

    If anyone tries "black holes explode" in google and doesn't get the article, try adding the author's name to the search and google "Cowen black holes explode".
     
  9. Aug 9, 2014 #8

    marcus

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    Jim,
    I checked my notes and past email correspondence---I should have said 1023 kg.

    This is about the mass of the Earth's moon. It is in the range thought possible for primordial BH, which could have formed in the very dense energetic early moments of expansion. Of course a BH of that mass would be very tiny--like a bit of grit--around a tenth of a millimeter radius.

    The idea is with that initial mass the thing would not have exploded YET but would be getting ready to explode about now.The expected lifetime of a BH (by this model) depends on the mass. It is proportional to the cube of the mass, if I remember correctly.
     
    Last edited: Aug 9, 2014
  10. Aug 9, 2014 #9
    Interesting thank you very much for your collected insights I will check out the nature paper


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