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

Information Preservation and Weather Forecasting for Black Holes

  1. Jul 8, 2015 #1

    Abstract: It has been suggested that the resolution of the information paradox for evaporating black holes is that the holes are surrounded by firewalls, bolts of outgoing radiation that would destroy any infalling observer. Such firewalls would break the CPT invariance of quantum gravity and seem to be ruled out on other grounds. A different resolution of the paradox is proposed, namely that gravitational collapse produces apparent horizons but no event horizons behind which information is lost. This proposal is supported by ADS-CFT and is the only resolution of the paradox compatible with CPT. The collapse to form a black hole will in general be chaotic and the dual CFT on the boundary of ADS will be turbulent. Thus, like weather forecasting on Earth, information will effectively be lost, although there would be no loss of unitarity.

    Has this been developed further? There's a lot of citations, but I'd be interested in hearing if any of you have been following this idea, since it was published and opinions on its current status.
  2. jcsd
  3. Jul 8, 2015 #2
    I think the analogy with weather is sound. Testing the predictions will be a challenge.

    After string theory with decades of work and few testable predictions, I think many may be gunshy about funding research that is short on testable predictions.
  4. Jul 8, 2015 #3
    I can understand that but it seems very vague left like that. It seems to make sense to clarify exactly what is being proposed
  5. Jul 9, 2015 #4
    The discussion is obviously high level and sophisticated, but Hawking's first citation upon which he seems to be commenting was published 2013 so it seems a continuing effort. The authors offer insights on alternatives but do not arrive at a firm conclusion, citing 'tensions' among alternatives. All I can say for sure is that this information issue and related issues like quantum cloning with regard to black holes has been around a long time. It's also been discussed in these forums a number of times.

    In one discussion, I posted these two quotes from THE BLACK HOLE WAR by Leonard Susskind [2008]:

    [Pg 223]
    At this point in the book Susskind says
    “ I have given you no possible way out of the dilemma. That’s because I don’t know the resolution…. Somehow we are missing a very deep point about information and how it is located in space”

    Sounds the issue is still a confounding one.

    Hawking is commenting on a paper by Polchinsky [UCLA] and others [his first citation]:

    Black Holes: Complementarity or Firewalls?
    Pg 13:
    4 Conclusions

    "....Historically, the black hole information paradox presented three main alternatives, each
    problematic: information loss, purity of the Hawking radiation, and remnants. The discovery
    of gauge/gravity duality pointed to purity, and to a fundamentally nonlocal formulation of
    quantum gravity. Our work again seems to present some sharp and perhaps unpalatable
    alternatives: a rewall at the horizon, or novel and probably nonlocal dynamics extending
    a macroscopic distance outside the horizon. (We note that the rewall also has elements of
    nonlocality, in that its location, the horizon, is not determined by any local feature but by a
    global property.) The second alternative has the potential to connect with one of the notable
    features of BHC, the fast-scrambling time scale, but our attempt to determine possible forms
    of the dynamics leads us to conclude that it would nevertheless cause notable violations of
    semiclassical physics at macroscopic distances from the horizon.
    The tensions noted in this work may lead the reader to wonder whether even the most
    basic coarse-grained properties of Hawking emission as derived in [34] are to be trusted.
    But the thermodynamic picture of black holes now rests on many pillars that remain intact.........
  6. Jul 9, 2015 #5
    For those interested, there is a current related thread on information loss with relevant comments from Marcus on the Hawking paper. I haven't read the paper yet but am a big fan of Rovelli's because he usually gives wonderfully insightful summaries of what he concludes from the mathematics. With all the assumptions, advanced math of both GR and quantum mechanics, and simplifying approximations usually involved it's not easy for those not immersed in the research to draw independent conclusions. Especially when different researchers approach similar subjects from different mathematics and draw different and sometimes conflicting conclusions. Quantum gravity is an active area of research and not for the mathematically faint-of-heart....

    White Holes Anyone?

    In particular see Marcus post #11, 12 which quotes NATURE on the issue of information loss, WH and BH.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook