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Stephen Hawking offers new resolution of black hole paradox

  1. Aug 25, 2015 #1

    marcus

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    Bee Hossenfelder was live-blogging from Stockholm Conference on BH info puzzle today Tuesday 25 August.
    Herewith:
    http://backreaction.blogspot.com/2015/08/hawking-proposes-new-idea-for-how.html

    The conference is 24-29 August. Hawking presented his idea Tuesday, based on joint work with Malcolm Perry (Cambridge) and Andy Strominger (Harvard). Perry also spoke today. According to the posted schedule for Tuesday, his talk was followed by talks by Carlo Rovelli and Francesca Vidotto.

    The conference will include a range of different ideas for resolving the BH information paradox.
    EDIT: videos of talk(s) may eventually appear at http://www.nordita.org/video/index.php?ev=hrad2015
     
    Last edited: Sep 2, 2015
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  3. Aug 25, 2015 #2

    marcus

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    Here's the press release about the conference from the Swedish host institution KTH:
    https://www.kth.se/en/aktuellt/nyhe...-aim-at-paradox-of-black-hole-theory-1.585138

    Here's the posted schedule of talks;
    http://www.nordita.org/hawkingradiation/program/index.php
    Here's the list of participants that was posted. I have highlighted the names of those scheduled to give talks:
    • Stephen Hawking, University of Cambridge
    • Jim Bardeen, University of Washington, Seattle
    • Philip Candelas, University of Oxford
    • Steve Christensen, UNIX Packages LLC
    • Ulf Danielsson, Uppsala University
    • Paul Davies, Arizona State University
    • Fay Dowker, Imperial College London
    • Michael Duff, Imperial College London
    • Larry Ford, Tufts University
    • Katie Freese, Nordita
    • Steve Fulling, Texas A&M University
    • Jim Hartle, University of California, Santa Barbara
    • Gerard t’Hooft, Utrecht University
    • Gary Horowitz, University of California, Santa Barbara
    • Werner Israel, University of Victoria
    • Claus Kiefer, University of Cologne
    • Jorma Louko, University of Nottingham
    • Laura Mersini-Houghton, University of North Carolina
    • Charles Misner, University of Maryland
    • Emil Mottola, Florida Atlantic University
    • Jack Ng, University of North Carolina at Chapel Hill
    • Jerome Novak, French National Centre for Science
    • Don Page, University of Alberta
    • Leonard Parker, University of Wisconsin, Milwaukee
    • Malcolm Perry, Cambridge University
    • Joe Polchinski, University of California, Santa Barbara
    • Carlo Rovelli, Aix-Marseille University
    • Philippe Spindel, University of Mons
    • Kelly Stelle, Imperial College London
    • Andy Strominger, Harvard University
    • Bo Sundborg, Stockholm University
    • Gerard 't Hooft, University of Utrecht
    • Paulo Vargas Moniz, Universidade da Beira Interior
    • Francesca Vidotto, Radboud University Nijmegen
    • Bob Wald, University of Chicago
     
  4. Aug 26, 2015 #3

    martinbn

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    I watched the video, but it is very brief. Can we see some of the details? He says that for the horizon of a stationary black hole one can define supertranslations in a similar way as for scri plus of an asymptotically flat space-time and they store the information of incoming particles. But how does it work, and what about evaporating black holes?
     
  5. Aug 26, 2015 #4

    marcus

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    We're told to expect a paper (from Hawking, Perry, Strominger) in September. I think what came out in Tuesday's talks by Hawking and, later, Perry was more of a teaser. Looking at Bee's blog for Tuesday I get the impression that she was left with a lot of questions. She made a brief reference to Perry's talk and said it cleared up some points.

    I'd be more interested in hearing about some of the other talks at the conference. I'll post the program to give an idea, from the talk titles, of some of the other ways the BH enigma is being addressed. I don't think Hawking has a monopoly on interesting lines of investigation. Indeed it might be prudent to take the "supertranslations" gambit with a grain of salt.

    Here's a condensed program (with lunches, coffeefbreaks, banquet etc deleted) just to give the titles of the talks by other participants:
    MONDAY, 24 August
    11.00 – 11.45 "Backreaction and Conformal Symmetry" G. 't Hooft
    14.15 – 15.00 "Backreaction of Hawking Radiation and Singularities" L. Mersini-Houghton
    16.00 – 16.45 "Physical interpretation of the semi-classical energy-momentum tensor in a Schwarzschild background" J. Bardeen
    TUESDAY, 25 August
    11.00 – 11.45 "The Information Paradox" S. Hawking
    14.15 - 15.00 "Black Hole Memory" M. J. Perry
    16.00 – 16.40 "Black to White Hole Tunnelling: Before or After Hawking Radiation?" C. Rovelli
    16.40 – 17.10 "A new Quantum Black Hole Phenomenology" F. Vidotto
    WEDNESDAY, 26 August
    11.00 – 11.45 "Black Holes as Open Quantum Systems" C. Kiefer
    14.15 - 15.00 "Particle Creation from vacuum in gravitational expansion and collapse" L. Parker
    16.00 - 16.45 "Gravitational Condensate Stars or What's the (Quantum) Matter with Black Holes?" E. Mottola
    THURSDAY, 27 August
    11.00 – 11.45 "Did the chicken survive the firewall" J. Louko
    14.15 – 15.00 "Gravity = (Yang-Mills)^2" M. Duff
    16.00 – 16.45 "Black holes and other solutions in higher derivative gravity" K. Stelle
    FRIDAY, 28 August
    11.00 - 11.45 "Quantum Damping or Decoherence: Lessons from Molecules, Neutrinos, and Quantum Logic Devices" L. Stodolsky
    14.15 – 15.00 "Puzzle Pieces: Do any fit?" Ch. Misner
    16.00 – 16.45 "The Generalised Second Law and the unity of physics" F. Dowker
    SATURDAY, 29 August
    11.00 – 12.00 Group Discussion: Summary of Results and Open Questions
    12.00 – 12.30 Status Report S. Hawking [TBC]
    12.30 – 13.00 Conclusions P. Davies
     
    Last edited: Aug 26, 2015
  6. Aug 26, 2015 #5

    marcus

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    We can check Bee's blog now and then for updates.
    http://backreaction.blogspot.com
    The latest update to the Tuesday post http://backreaction.blogspot.com/2015/08/hawking-proposes-new-idea-for-how.html was that another talk by Malcolm Perry had been scheduled for Wednesday (today) and that the plan was to record it and post the video at the Nordita website.
    Presumably that would be here:
    http://www.nordita.org/video/index.php
    but I don't see it...
     
    Last edited: Aug 27, 2015
  7. Aug 26, 2015 #6

    anorlunda

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    Isn't he just saying that Gerard t’Hooft, and Leonard Susskind were right all along, or is he saying something different, or am I oversimplifying?
     
  8. Aug 26, 2015 #7

    marcus

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    't Hooft is at the conference and gave a talk Monday. What might he be saying about BH? Here's the most recent 't Hooft BH paper I could find:
    http://arxiv.org/abs/0909.3426
    Quantum gravity without space-time singularities or horizons
    Gerard 't Hooft
    (Submitted on 18 Sep 2009)
    In an attempt to re-establish space-time as an essential frame for formulating quantum gravity - rather than an "emergent" one -, we find that exact invariance under scale transformations is an essential new ingredient for such a theory. Use is made of the principle of "black hole complementarity", the notion that observers entering a black hole describe its dynamics in a way that appears to be fundamentally different from the description by an outside observer. These differences can be boiled down to conformal transformations. If we add these to our set of symmetry transformations, black holes, space-time singularities, and horizons disappear, while causality and locality may survive as important principles for quantum gravity.
    10 pages, 3 figures. Presented at the Erice Summerschool of Subnuclear Physics 2009

    The title of his 2015 Stockholm talk "Backreaction and Conformal Symmetry" seems remarkably in line with this 2009 Erice paper! He may not have changed focus very much over the past 6 years, in his thinking about BH. I wish we had access to 't Hooft's talk.

    A sample of Susskind's recent BH thinking:
    http://arxiv.org/abs/1411.0690
    Entanglement is not Enough
    http://arxiv.org/abs/1403.5695
    Addendum to Computational Complexity and Black Hole Horizons
    http://arxiv.org/abs/1402.5674
    Computational Complexity and Black Hole Horizons

    Links possibly more relevant to what S.H. is talking about:
    http://people.maths.ox.ac.uk/lmason/NGSA14/Slides/Arthur-Lipstein.pdf
    http://iopscience.iop.org/1742-6596/283/1/012023/pdf/1742-6596_283_1_012023.pdf
     
    Last edited: Aug 27, 2015
  9. Aug 26, 2015 #8

    MTd2

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    One of the people who led to this claim are some papers authored and co authored by an undergraduate 19 year old girl.
     
  10. Aug 27, 2015 #9
    Who is she ?
     
  11. Aug 27, 2015 #10
    Ugh nothing worse than these drama talks only ment to confuse people :|
     
  12. Aug 27, 2015 #11

    MathematicalPhysicist

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    How do they plan to resolve the BH information paradox, is there any empirical experiment which is planned to resolve this paradox?
     
  13. Aug 27, 2015 #12

    marcus

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    At least for the time being (in its present incomplete form) Hawking et al's proposal seems to have bombed. Bee writes:
    http://backreaction.blogspot.com/2015/08/embrace-your-5th-dimension.html
    ==quote==
    ... Essentially he is claiming that our universe has holographic properties even though it has a positive cosmological constant, and that the horizon of a black hole also serves as a surface that contains all the information of what happens in the full space-time. This would mean in particular that the horizon of a black hole keeps track of what fell into the black hole, and so nothing is really forever lost.

    This by itself isn’t a new idea. What is new in this work with Malcom Perry and Andrew Strominger is that they claim to have a way to store and release the information, in a dynamical situation. Details of how this is supposed to work however are so far not clear. By and large the scientific community has reacted with much skepticism, not to mention annoyance over the announcement of an immature idea.
    ==endquote==
     
  14. Aug 27, 2015 #13

    martinbn

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    Why does she say that!? Presumably from discussions at the conference, but from the announcement it seems to me that they do not say that the event horizon contains all the information in the full space-time, but just the information for the matter that falls in.
     
  15. Aug 27, 2015 #14

    marcus

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    A wide-audience wrap-up of the Hawking side of the conference, in SciAm:
    http://www.scientificamerican.com/a...asn-t-solved-the-black-hole-paradox-just-yet/

    It's unfortunate that no information is coming out about the other talks given at the conference. There were over a dozen other speakers on the program (including 't Hooft and several others well worth listening to) presenting other approaches to BH issues.
    The organizers are missing an opportunity by not putting video online of talks like these and the ensuing discussion by the other participants:
    "Backreaction and Conformal Symmetry" G. 't Hooft
    "Puzzle Pieces: Do any fit?" Ch. Misner
    "The Generalised Second Law and the unity of physics" F. Dowker
     
  16. Aug 27, 2015 #15

    marcus

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    Contains the information, as you say, and contains it classically, in the metric,which is somewhat surprising. IOW a BH has an enormous amount of hair, even at the classical level.

    I suspect the HPS idea may be too half-baked to discuss at this point (but that's up to the expert participants to decide). To give an idea of possible reactions in the physics community:
    ==quote==
    http://backreaction.blogspot.com/20...howComment=1440613730548#c6764159180892586245
    transumante said...

    The only clear thing is that none [of the audience] understood anything. Is this a new way of communicating scientific results? As a sybilline facebook status? Suspense, photographs, vague announcements? Why didn't they wait to submit the paper without any sensationalistic preview?

    It is even more sad when renowned top scientists behave in this way.


    http://backreaction.blogspot.com/20...howComment=1440653755354#c5948626407447527793
    transumante:

    I can assure you that pretty much every one in the community thinks the same. Look, you shouldn't take Hawking as being representative for contemporary research. He is an extreme statistical outlier on all accounts. I have no idea why he wanted to announce his conclusion here and now. Maybe it was just because it was a good occasion and the timing seemed right, or because he likes Stockholm. It's certainly not something people commonly do. The standard procedure is, do the work, publish the paper, give the talks, and that's what the vast majority of physicists do. Every once in a while of course the timing goes wrong and somebody gives a talk about an almost-done work, or a yet-to-appear paper, and so on. Maybe it's a case like this, maybe the paper was supposed to appear earlier, but I don't know really. Best,

    B.
    ==endquote==
     
    Last edited: Aug 27, 2015
  17. Aug 27, 2015 #16
    By and large the scientific community has reacted with much skepticism, not to mention annoyance over the announcement of an immature idea.

    This could mean it is groundbreaking.

    When was the last time a great breakthru was widely and wildly 'accepted'?? It wasn't GR.
     
  18. Aug 27, 2015 #17

    MTd2

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  19. Aug 27, 2015 #18

    MTd2

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    I think for Stephen Hawking is a different thing. He looked so fragile on his presentation. He was manipulating his computer with a move detector attached to his glasses, which read tiny movements of the right of his lips and eyebrows.

    I think he was trying to take to make the best of his time to at least share his ideas (this one specifically was only 1 month old at the day of the presentation).
     
    Last edited: Aug 27, 2015
  20. Aug 27, 2015 #19

    marcus

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    Sabrina Gonzalez Pasterski
    is listed as 22 years old in a July 2015 article about her. But earlier this year when she was written up, she was 21.
    I understand she is a first generation Cuban-American raised in Chicago. Her parents would have emigrated from Cuba.
    Chicago has a regional school for the gifted, she went to MIT for undergrad and IIRC graduated at the top of her class, or something amazing like that. She has done a lot of remarkable things like build and fly her own experimental aircraft. So as a 21 year old she was in the PhD program at Harvard, collaborating with Strominger and others on papers like this:
    http://arxiv.org/abs/1502.07644
    Higher-Dimensional Supertranslations and Weinberg's Soft Graviton Theorem
    Daniel Kapec, Vyacheslav Lysov, Sabrina Pasterski, Andrew Strominger
    (Submitted on 26 Feb 2015)
    Asymptotic symmetries of theories with gravity in d=2m+2 spacetime dimensions are reconsidered for m>1 in light of recent results concerning d=4 BMS symmetries. Weinberg's soft graviton theorem in 2m+2 dimensions is re-expressed as a Ward identity for the gravitational S-matrix. The corresponding asymptotic symmetries are identified with 2m+2-dimensional supertranslations. An alternate derivation of these asymptotic symmetries as diffeomorphisms which preserve finite-energy boundary conditions at null infinity and act non-trivially on physical data is given. Our results differ from those of previous analyses whose stronger boundary conditions precluded supertranslations for d>4. We find for all even d that supertranslation symmetry is spontaneously broken in the conventional vacuum and identify soft gravitons as the corresponding Goldstone bosons.
    24 pages

    She also collaborated with Strominger and friends on some less explicitly related papers in 2014.
     
    Last edited: Aug 27, 2015
  21. Aug 27, 2015 #20

    MTd2

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    Recently, Raphael Bousso came up with 2 breakthroughs in GR and holography:

    http://arxiv.org/abs/1506.02669
    http://arxiv.org/abs/1504.07660

    His PhD adviser was Stephen Hawking.

    I really like theories whose fundamentals and basic forms can be explored and expressed with high ratio of ideas/(math expressions).
     
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