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The Very Early Universe meeting

  1. Dec 4, 2007 #1

    cristo

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    This meeting is taking place at Cambridge University in a couple of weeks time to commemerate a meeting that took place 25 years ago, on this very topic (and partly, I think, to publicise its new "Centre for Theoretical Cosmology" that is opening soon).

    The list of speakers is quite remarkable, including Guth, Bardeen, Hawking, Liddle, Lyth, Rees, Hartle, Kolb, Turner, Linde, Steinhart etc..

    Apparently it was first meant to be a small meeting, but is now opened up to members of any university. Unfortunately, since us common folk only got told about it today, I won't be able to afford to go, so I'm not even bothering to apply; but I have been told that videos of the lectures will be available on the web!!
     
    Last edited: Dec 4, 2007
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  3. Dec 4, 2007 #2

    marcus

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    Last edited: Dec 4, 2007
  4. Dec 7, 2007 #3

    cristo

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    Since my last post, I changed my mind and decided to apply anyway. I received an email this evening telling me that my application had been successful! I think it'll be a great experience for someone like me, who's starting out in the field. Now I just have to beg my department for some money!

    I'll post afterwards about any of the specifically interesting talks; although looking down the list, not one looks uninteresting!
     
  5. Dec 8, 2007 #4

    hellfire

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    This is great. The program is impressive. Keep us informed!
     
  6. Dec 9, 2007 #5

    Chronos

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    Listen well, and report with enthusiasm, grasshopper . . .
     
  7. Dec 9, 2007 #6

    Kurdt

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    Thats fantastic cristo. I hope you have a good time there and I look forward to reading about your experiences.
     
  8. Dec 14, 2007 #7

    cristo

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  9. Dec 14, 2007 #8

    Kurdt

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    Oh cool. Ian Moss is there. He was my tutor.

    Some huge names there cristo. Wilczek, Liddle, Hartle, enjoy it! :smile:
     
    Last edited: Dec 14, 2007
  10. Dec 17, 2007 #9

    cristo

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    So, I'm back from the first day at the conference and have to say I'm very fortunate for my first ever conference to be so huge. I was also lucky to have a postdoc from my department sat next to me, who pointed out all the 'famous' people to me! I'll give a brief summary, although I won't even attempt to write detailed notes here on the talks!

    The opening talk of the conference was given by Alan Guth. I have to say he was a good choice, not only since he's one of the fathers of inflation, but he's also a really good speaker. He began with a brief description of the conference that took place 25 years ago. He dug out the schedule, and his handwritten notes from that conference; pointing out that in the first week of the last conference there were 10 talks, compared to 11 in the first day this year, which he attributed to inflation (the first of many "jokes" about inflation!) The notes he said he will make available at this URL, http://ctp.lns.mit.edu/~guth/VEUmemories.html, presumably sometime next week. Then he spoke about the successes of inflation, and also explained the answer to a question I asked spacetiger for references for the other day; namely that of eternal inflation. The "bottom line" of his talk was that we have never had a model of the universe that both works so well, but is also so mysterious.

    The second speaker was another of the greats (I'm sure I'm going to use that phrase a lot in this summary!); namely Alexei Starobinsky. His talk was mainly on stochastic inflation. He spoke well for the first part, but then was rushed towards the end: it's a bit of a shame really, since I could have sat and listened to him for hours! He stressed the need for new observational evidence, and said that going back to the history of the universe is possible, but we require new measurements of some new "light scalars."

    Next was Demos Kazanas. He spoke about cosmological inflation from a personal perspective, detailing his career in the field. Then we had morning coffee break (which I welcomed, since I'm not used to these early mornings!)

    The first speaker after the break was Stephen Hawking, answering the question 'why did the universe inflate.' His talk was mainly on the no boundary condition and a semiclassical approximation to the wavefunction of the universe. I have to say that listening, and seeing Prof Hawking give a seminar made me in awe of him. He answered a question at the end of his talk, which took him a while to "type" out into the voice synthesiser, and it just hit me that this guy does everything in his head. If he did have the physical capabilities of the rest of us, then he'd be an extraordinary scientist, but to be able to do what he does without writing anything down, or even being able to quickly converse with people is utterly amazing. He is clearly devoted to science, because seeing the amount of effort it takes him to talk shows that it would have been a lot easier for him to give up years ago. Anyway, he concluded that 'volume weighting gives a high probability of a large amount of inflation.

    Next up was Andrei Linde who spoke about the general inflationary paradigm, models of inflation (inflaton+curvaton) and alternative models (ekpyrotic/cyclic scenario). He concluded that string theory can describe inflation in the early universe as well as inflation now; and that eternal inflation and string theory have joined each other in the landscape.

    After lunch, Katsuhiko Sato spoke about supernovae data, and multiproduction of universes. He commented on three papers that he had published before Guth, and then discussed how 'mushroom' wormholes start a multiproduction of universes. After him Paul Steinhardt discussed inflationary and cyclic models of the universe. He pointed out some problem with inflation (unpredictability, persistence of memory, geodesic incompleteness, entropy problem), and then sought a model that didn't have these problems; namely the cyclic or ekpyrotic model. He ended by pointing out observational predictions of the model regarding gravitational waves and non-gaussianity.

    Slava Mukhanov gave the next talk, on cosmological perturbations: theory vs observations. He discussed the need to amplify the quantum fluctuations in an expanding universe, and discussed how they transfer from the planckian scale to the galactic scale through Hubble expansion.

    The talk immediately after tea was by Jim Bardeen, entitled 'Backreaction as an explanation for DE?' Now, I've read a few of his papers, and have to say that I found them pretty tough, so expected his talk to be difficult to understand. It didn't turn out to be too bad; he discussed gauge choices and gauge invariant quantities. He then mentioned some of the recent backreaction papers like those by Wiltshire and Kolb et al. He then spoke of the counter arguments to these, from Wald, Flanagan. To conclude he said that 'Newtonian gravity is a good description in the presence of large perturbations, and that there is no significant backreaction.'

    Next up was Henry Tye, talking about "brane inflation: an update." I found this talk very interesting. He started by discussing how inflation exhibits itself in the string environment, then went on to discuss in more detail one of these ways; namely brane inflation. He mentioned brane antibrane scenarios, and the annihilation of the branes ending inflation. Then, he spoke about possible non-gaussianity from two models of inflation: multifield inflation and DBI (Dirac-Born-Infeld) inflation. Finally, he mentioned how one may use the gauge theory/gravity duality in order to 'measure' the warp geometry of the throat in the bulk.

    The final talk was by Ian Moss, who was meant to talk about the Hartle-Hawking state but, since both authors were talking about this, changed his talk to "Thermal Fluctuations. " Basically, this entailed looking at thermal fluctuations instead of density fluctuations. HE outlined a theory (which I'll skip over) and concluded that the there is a way to determine this model from multi-scalar field theories.

    And, that was the end of the first day. I have to say I'm pretty tired, but had a brilliant day. And, looking at the schedule for tomorrow, it looks like more of the same high quality!
     
  11. Dec 17, 2007 #10

    Kurdt

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    I managed to watch the last three online cristo, and I was anticipating Bardeen's talk. I must say I was slightly disappointed at his presentation since he seemed so nervous as to be unable to get any rhythm going. Never the less it was very interesting.

    Tye gave a very good presentation, little of which I understand, and it was just good to see Ian Moss again.
     
  12. Dec 17, 2007 #11

    cristo

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    I agree. To be honest, I'm not sure how presentable you can make perturbation theory (I may have to learn, though!) He did include a lot of formulae and lots and lots of text on the slides!

    Yes, Tye's was good, and I liked Ian Moss' talk too, although didn't understand too much of it. He had trouble trying to get through to the person on the back row who asked the first question though! :rofl:
     
  13. Dec 17, 2007 #12

    Kurdt

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    That same person on the back row gave Bardeen quite a hard time as well if I remember correctly. I used to love Moss' cosmology lectures because he teaches in that exact same style. Quite eccentric yet very clever and endearing.
     
  14. Dec 17, 2007 #13

    cristo

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    Yea, he asked quite a bit early on too; there's always one! However, these were the sorts of speakers who were not afraid of answering "i don't know" or "that's interesting.. let's discuss it later," and so weren't able to be caught out by any questions.

    I imagine he teaches like that. I particularly enjoyed his comment that some of his slides were "lifted straight from his undergrad course!" You were very lucky to be taught by someone of that ability and intelligence!

    Are you planning on watching any tomorrow, Kurdt? Obviously, I'm looking forward to all of them, but especially those by Liddle, Lyth and Bond.
     
    Last edited: Dec 17, 2007
  15. Dec 17, 2007 #14

    Kurdt

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    I still have those lecture slides on my PC. I plan on watching some tomorrow if time permits. I would like to see Wilczek, Liddle, Hartle and the last three speakers. I'll see what happens. :smile:
     
  16. Dec 17, 2007 #15

    cristo

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    Wilczek was preparing his talk on his laptop in the row in front of me this morning. It looks interesting, although a little particle-physicsy! I hope you get the time to watch some.
     
  17. Dec 17, 2007 #16

    hellfire

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    From the programme I infer that 25 years after the Nuffield Workshop the discussion topics are basically the same but are handled from a slightly different perspective. At that time inflationary models were being defined, now they are being fully deployed from several perspectives. Observational signatures are identified here and there, probably waiting for Planck to give some veredict. Inflation seems to be a very settled paradigm, but it surprises me the lack of ideas or talks about new ideas and models that should explain inflation. The workshop focuses on inflation and its consequences instead of asking about the origins. May be we are still too far away?
     
  18. Dec 18, 2007 #17

    Kurdt

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    Unfortunately I missed today (as I thought I would) because I had other commitments. The same will probably apply tomorrow.
     
  19. Dec 31, 2007 #18
    Thanks for the nice report. Does anyone know if the videos of the talks are archived
    and if so, could they provide a link to those?
    thanks
     
  20. Dec 31, 2007 #19

    marcus

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    Mark, you asked about archived videos. The above links have PDF and Powerpoint files of the SLIDES used in the talks. These often spell out a lot of what was said.

    The program page has a link for live streaming, may also have things on file
    it says:

    Go to the website
    1.Enter sign in name (any will do)
    2.Conference ID is: 0796
    3.Select High or Low bandwidth
    4.Select stream this conference

    My guess is that this was ONLY for live streaming. I tried it and got nothing.

    I looked around and didn't see any evidence of archived video. If someone else finds some I'd be glad to know about it too. For the moment there are at least the PDF files of the slides for several of the talks.
     
    Last edited by a moderator: Mar 4, 2015
  21. Dec 31, 2007 #20
    Yes, I saw the slides. In fact Mike Turner's closing talk refers to this thread :-)
    I was hoping people here would know if videos of talks are archived. If they were streamed, I am sure they have been saved . Also I am glad that Kazanas gave the opening talk. Unfortunately very few people cite Kazanas paper
    http://adsabs.harvard.edu/abs/1980ApJ...241L..59K (which are before Guth's 1981 paper)
     
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