Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Firewall paradox resolved?

  1. Feb 1, 2014 #1

    bcrowell

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    This blog post https://medium.com/starts-with-a-bang/df0a131d7b95 by Ethan Siegal claims that the firewall paradox is resolved. The papers it refers to are:

    Samuel L. Braunstein, Stefano Pirandola, Karol Życzkowski, "Better Late than Never: Information Retrieval from Black Holes," http://arxiv.org/abs/0907.1190

    Erik Verlinde, Herman Verlinde, "Passing through the Firewall," http://arxiv.org/abs/1306.0515

    S. Hossenfelder, "Disentangling the Black Hole Vacuum," http://arxiv.org/abs/1401.0288

    Is he right?
     
  2. jcsd
  3. Feb 1, 2014 #2

    marcus

    User Avatar
    Science Advisor
    Gold Member
    Dearly Missed

    An alternative way to show that all information is eventually recovered and unitarity upheld.
    Fairly straightforward consequence of LQG bounce (in slow motion because deep in gravity well):

    http://arxiv.org/abs/1401.6562
    Planck stars
    Carlo Rovelli, Francesca Vidotto
    (Submitted on 25 Jan 2014)
    A star that collapses gravitationally can reach a further stage of its life, where quantum-gravitational pressure counteracts weight. The duration of this stage is very short in the star proper time, yielding a bounce, but extremely long seen from the outside, because of the huge gravitational time dilation. Since the onset of quantum-gravitational effects is governed by energy density --not by size-- the star can be much larger than planckian in this phase. The object emerging at the end of the Hawking evaporation of a black hole can then be larger than planckian by a factor (m/mP)n, where m is the mass fallen into the hole, mP is the Planck mass, and n is positive. The existence of these objects alleviates the black-hole information paradox. More interestingly, these objects could have astrophysical and cosmological interest: they produce a detectable signal, of quantum gravitational origin, around the 10−14cm wavelength.
    5 pages, 3 figures.

    The authors explicitly reject the "firewall" idea as unnecessary. The fact that this model of BH evaporation does not require inventing a firewall or anything else especially exotic seems to be a point in its favor.
     
  4. Feb 1, 2014 #3

    atyy

    User Avatar
    Science Advisor

    Doesn't Hossenfelder's paper propose that the outgoing radiation is pure, contrary to Siegel's blog post?

    Another set of ideas I like are those of Papadodimas and Raju. I think the problems with their initial proposal were the state dependence of the construction and that their initial analysis was for a non-evaporating black hole. I don't think the state dependence is necessarily a problem, because one can imagine that the emergent geometry is dependent on the state. Their latest analysis extends the work a little to non-equilibrium situations.
    http://arxiv.org/abs/1211.6767
    http://arxiv.org/abs/1310.6334
    http://arxiv.org/abs/1310.6335

    Hossenfelder thinks her proposal is consistent with the Verlindes's, and a later paper from the Verlindes indicates they think their proposal is consistent with that of Papadodimas and Raju.
    http://arxiv.org/abs/1311.1137

    So it would be interesting if Hossenfelder's proposal were consistent with Papadodimas and Raju's. In her discussion, she says it's a future direction. I hope she writes more about that in the future.
     
    Last edited: Feb 1, 2014
  5. Feb 2, 2014 #4

    marcus

    User Avatar
    Science Advisor
    Gold Member
    Dearly Missed

  6. Feb 3, 2014 #5

    MathematicalPhysicist

    User Avatar
    Gold Member

    Well, some theory or model is right when you can physically test it, or my pragmatic idea of rightness is wrong?
    (Besides of course of mathematical inconsistencies, which I assume someone will have spot it already).
     
  7. Feb 3, 2014 #6

    Chronos

    User Avatar
    Science Advisor
    Gold Member

    I think the whole firewall thing was merely a ruse intended to spur scientists to think outside the box.
     
  8. Feb 3, 2014 #7

    marcus

    User Avatar
    Science Advisor
    Gold Member
    Dearly Missed

    That's an interesting take on it! :biggrin: Rovelli Vidotto's solution is remarkably simple once you see it. Given what Steve Giddings pointed out already in the 1990s (!) about a massive replacement for the temporary "singularity"…you just have to notice that is precisely what the LQG picture provides because of gravitational redshift (time dilation.)
    .
     
  9. Feb 3, 2014 #8

    Haelfix

    User Avatar
    Science Advisor

    In short no he is not. There is absolutely no agreement or consensus amongst experts at the moment, and there really hasn't been a single paper that has satisfactorily resolved the original AMPs argument or any of the new variants. Every single proposal on the market has pretty serious theoretical issues even the serious ones like the Verlinde paper, so it remains an open and vexing problem at this time.

    The Verlinde square paper is an example of what is known as strong complementarity and is one of the main ideas that people have tried to use to resolve the paradox, but even that is not without its problems (state dependance, genericity etc).

    See here for recent commentary and a review by Polchinski:
    http://online.kitp.ucsb.edu/online/qft14/polchinski/
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Firewall paradox resolved?
  1. Black Hole Firewalls (Replies: 83)

Loading...