Which conference lineup interests you more? (Strings '11 or mixed-QG 11)

[weburbia]

There were some explanations for the unexpected high cost of strings 11 in comments at http://www.math.columbia.edu/~woit/wordpress/?p=3689 (weak USD strong SEK, VAT)

It is good that a conference has been organised to try to bring different groups together. it would be good to hear from some participants about whether it worked or if the speakers just flew into give their talks and left.

To really make things happen they need to fund research programs with the specific purpose to look for cross-over, especially between string theory and other QG approaches.

 

[Fra]

*Strings website says the reg fee is 5000 Krona now or a bit over 5600 SEK at the door, divide by 6.38. You know the exchange rate better than I. Around $800. To me that says it's hard to get the likes of Wilczek and Witten to come and be names at a dull conference. But who knows? maybe stuff is just very expensive in Sweden. :-)

I'm not sure what the normal price for such a conference is so I don't have an opinion, but I know the concert hall building where they are holding the seminars is a newly built one and was a controversial project and beeing running at economic loss so far from what I know, it probably isn't the cheapest place of choice.

The "public semniars" with Greene et all are sold out according the website, with no seats left.

/Fredrik

 

[marcus]

I'm not sure what the normal price for such a conference is so I don't have an opinion, but I know the concert hall building where they are holding the seminars is a newly built one and was a controversial project and beeing running at economic loss so far from what I know, it probably isn't the cheapest place of choice.

The "public semniars" with Greene et all are sold out according the website, with no seats left.

/Fredrik

The Zurich conference reg fee is 50 Swiss franc, or 100 CHF including the banquet dinner.
http://www.conferences.itp.phys.ethz.ch/doku.php?id=qg11:payment
50 Swiss is about $60. Order of magnitude less than the $800 fee at Strings 2011 Uppsala.

The link which Weburbia provided suggests that the Uppsala organizers expected "over 500 string theorists" to participate.* As of now 22 June only 261 registered as participants so they may have miscalculated---or maybe last minute reg will bring it up.
In any case if they would just charge admission to the Public Lectures by Stephen Hawking's daughter and Brian Greene and Andrei Linde it could help quite a bit with the bottom line.

http://www.conferences.itp.phys.ethz.ch/doku.php?id=qg11:programme
http://www-conference.slu.se/strings2011/programme_NEW.html
https://www.akademikonferens.se/list.jsf?conf=strings2011-S (link has been fixed)
Live streaming (starts monday 27 June):http://media.medfarm.uu.se/live1
Exchange rates, if anyone cares to they can convert both SEK and CHF to EU for comparison: http://www.oanda.com/currency/converter/

*I checked http://www-conference.slu.se/strings2011/index.html and confirmed the figure of "over 500 string theorists"
==quote from the Uppsala index page==

Strings is an annual conference gathering more than 500 researchers in string theory from all around the world. Since the 1980s, it has grown to be the largest and most important conference in the field. International experts are invited to review the most recent achievements in string theory and discussions between the participants lead to new developments and insights. Following the tradition of Strings conferences, public lectures will be given presenting aspects of string theory to a general audience...
==endquote==

Martin Reuter's talk is largely based on http://arxiv.org/abs/1012.4280 confirming that the Immirzi parameter has been adopted in AsymSafe QG.
He is going with the Holst action. Much of his talk is about the Immirzi. He has it run. So it is gamma_k instead of plain gamma. Interesting development, puts AsymSafe on much the same track as Loop gravity/cosmology.

==============================
EDIT TO RESPOND TO THE FOLLOWING POST #39 by Eiyaz

Eiyaz, someone else who follows string research more closely and with more interest than I would no doubt wish to answer. So I won't write a post #40 that would cover up yours on the index page. Personally I think that the mounting evidence against SUSY seriously detracts from String prospects.
It is indeed an uncomforable elephant that many steadfastly minimize or ignore. But the mathematical techniques can still be used in various contexts. Just not to expect a unique comprehensive stringy theory of nature.
On another topic, AdS/CFT, you might find this interesting:
http://www.math.columbia.edu/~woit/wordpress/?p=3793#comment-94039
a string theorist (or someone of that persuasion) who nonetheless strikes me as exceptionally frank and forthcoming.

 

[eiyaz]

Marcus thanks for posting this!

Once again I am confused, how is it that none of the lectures involve the failures of SUSY and how to compensate for that. Am I over emphysizing the importance of SUSY to string theory? My professor at college (undergrad class) had briefly stated that although SUSY is not required for ST, the most promising models suggest it. Therefore EDM uniformity and the lack of detection of SUSY removes the most promising models of ST.

In fact in Blau's paper "String Theory as a Theory of Quantum Gravity: A Status Report" he states:

Supersymmetry: Required for stability of string theory / allows controlled calculations - significance for quantum gravity in general beyond that? (but strongly coupled gauge theories without supersymmetry have regretful tendency to exhibit instabilities; and who knows what happens when one includes full set of standard model fields in other approaches to quantum gravity)

and

"Space is Emergent! When Xa diagonal ) interpretation as ordinary space-time coordinates of N D0-branes. For these “flat directions” of the potential to be preserved by quantum corrections, supersymmetry is essential!"

Yet he does not mention SUSY any further in the article. I have not read all the articles for ST, but so far it seems String theorists are brushing aside the problem of SUSY and ST. Do any of the papers cited talk about the 2011 indiction of SUSY and how it effects ST?

Is this the biggest elephant in the closet for string theorists or is it not as big a deal as I believe?

EDIT TO RESPOND TO THE FOLLOWING POST #39 by Eiyaz

Eiyaz, someone else who follows string research more closely and with more interest than I would no doubt wish to answer. So I won't write a post #40 that would cover up yours on the index page. Personally I think that the mounting evidence against SUSY seriously detracts from String prospects.
It is indeed an uncomforable elephant that many steadfastly minimize or ignore. But the mathematical techniques can still be used in various contexts. Just not to expect a unique comprehensive stringy theory of nature.
On another topic, AdS/CFT, you might find this interesting:
http://www.math.columbia.edu/~woit/wordpress/?p=3793#comment-94039
a string theorist (or someone of that persuasion) who nonetheless strikes me as exceptionally frank and forthcoming.

Wow! I was looking (actually more like skimming) through the paper titles and not one paper focuses on SUSY which is surprising given how big this year's revelations are. Are scientists ignoring this to protect their life work? It seems like the ostrich sticking its head in the sand.

 

[Fra]

Fra! take a look at Chamseddine's slides PDF. Gives some help understanding of how the Standard Model arises from Noncommutative Geometry.

I'll try to look at that later. As usual my todo list is constantly truncated.

I'm first reflecting a second round on my take on the "generalisation" of GSL that Jacobsson seeks.

The relative entropy is the same as kullback-leibler divergence and this is a natural measure that appears also in the ponderigns I've done when you try to consider "probabilities" for a future sequence of events. But it's as a pure discrete measure, and there it's always finite because there is not continuum underlying it. So in my picture all proper inside view are what Jacobsson calls "nice". No inside observer can measure it infinite.

In particular am I trying to see the connection. I think the general understanding we seek must be completely release from geometric notions. The notion of causal horizon is pretty much the communication channel, throug which all inferencs are made. I like the direction of Jacobssons papers as it goes well in line with inferencial thinking I am into.

There is also a direct connection to hawking radiation, when you consider how an inside observer; communicating through a "horizon" if assumed to NOT accumulate information; needs to discard information at the same rate new arrives. I have long been pretty sure that this "discarded information" is somehow directly related to hawking radiation. And if you see it tis way, it's actually clear that it this "radiation" contains no information RELATIVE to the emitter(this in fact also explains WHY it's emitted! it CAN not be retained/controlled; it's a "random" release), but this conclusion generally does not hold relative to the environment. Thus a resolutio nof the paraodox is then that the BH is "black" from the inside, but not from the outside. Ie. hawking radiation DOES contain information. (it's just that this is observer dependent)

But the missing connection is that the original conjectures take place in SPACETIME. I'm picturing this in terms of abstract inferences. what is missing is how to reconstruct 4D spacetime from pure abstract communication and channels.

For me Jacobsson's paper provides no clues to this personal quest of mine howto connect tothis, but I enjoy to see his focus on what I think are key points.

/Fredrik

 

[marcus]

The title of Derek Wise's talk is now posted. As may have been expected it is about 2-group representations. I'm going to do an update of the Zurich QG programme with some minor reclassification.
I don't have enough clearly distinct colors to show how diverse the Zurich conference mix actually is. Also some of my guesses may be wrong, so you have to finish the job of sorting it out "Foundations and general considerations" turned out to be an important category---basic thinking that could apply across the board---not just to one specific approach. I gave it a brighter color.

Slides PDF are available for (by now) 28 of the 38 talks listed. The links to the slides for those talks are here:
https://www.physicsforums.com/showthread.php?p=3369438#post3369438

Quantum Theory and Gravitation conference ("QG11") programme partially color-coded to show the mix.

Foundations-general considerations
String
Spectral Action (Connes Noncommutative Geometry) 2-Groups and Hgher Gauge Theory
Causal Dynamical Triangulations(CDT)
LQG (incl. Group Field Theory)
Asymptotic Safety
Supergravity, Noncommutative QFT, Massive Gravity, and other.
====

Ambjorn: CDT, a quantum theory of geometry
Arnlind: Poisson Algebraic Geometry and Matrix Regularizations
Ashtekar: Quantum Cosmology and the Very Early Universe
Bachas: The problem of localization of gravity
Baez: Higher gauge theory, division algebras and superstrings
Barrett: State sum models and the spectral action
Beisert: Symmetries and Integrability for Scattering Amplitudes in N=4 Super Yang-Mills Theory
Blau: String Theory as a Theory of Quantum Gravity: a Status Report
Bodendorfer: Towards Loop Quantum Supergravity
Bossard: Toward the consistency of N=8 supergravity as a quantum field theory
Chamseddine: The Spectral Action
Compere: The translation anomaly of asymptotically flat spacetimes
Craps: Cosmological singularities in string theory
de Goursac: Renormalizability of noncommutative quantum field theories
Dixon: Ultraviolet behavior of quantum (super)gravity through four loops
Elvang: Symmetry constraints on the UV behavior of N=8 supergravity
Freidel: The principle of relative locality
Giulini: Very basic issues concerning quantum mechanics and gravitation
Hollands: Quantum field theory correlators on manifolds at very large and very short distances
Hoppe: Fundamental Structures of M-brane Theory
Jacobson: How general is the generalized second law?
Lechner: Covariant and local deformations of quantum field theories
Lewandowski: Canonical LQG: soluble models and other advances
Litim: Renormalisation group and the Planck scale
Loll: Nonperturbative highlights on quantum gravity from CDT
Longo: Boundary Quantum Field Theory and Conformal Field Theory
Morton: Extended Field Theories and Higher Gauge Theories
Mukhanov: Massive Gravity
Nicolai: Infinite-dimensional symmetries and the Wheeler-DeWitt equation
Oriti: Group field theory: a brief survey of recent developments
Reiterer: A class of gauges for the Einstein equations
Reuter: Einstein-Cartan Theory and Asymptotic Safety
Rovelli: Loop quantum gravity: the covariant dynamics
Shaposhnikov: Scale-invariant alternatives to general relativity
Speziale: Spin networks as twisted geometries
Steinacker: Matrix models, noncommutative gauge theory and emergent geometry
Wise: 2-Group Representations and State Sum Models
Wulkenhaar: Ward identities in matrix models arising from noncommutative geometry

http://www.conferences.itp.phys.ethz.ch/doku.php?id=qg11:programme
http://www-conference.slu.se/strings2011/programme_NEW.html
https://www.akademikonferens.se/list.jsf?conf=strings2011-S (the link to the Uppsala participants list has been fixed.)

 

[atyy]

Given that Witten founded the "gravity is topological" movement which lies behind so much of loops, couldn't strings be seen as the more diverse conference?

 

[marcus]

Hi Atyy,

Wouldn't you agree that mere diversity is of itself not especially desirable. I think the organizers were aiming at an intelligent mix of people who are doing creative work (of different sorts) right now, in the present---and whose work and ideas could on the whole be potentially of use to the others. Like planning a lively party introducing new people to each other.

When I first saw the list of speakers, I didn't realize how well it was going to turn out. I only began to reaiize how well the mix was thought out when I saw the titles. And even then in many cases I had to look at the slides PDFs before I saw how some of the pieces fit together.

We don't know the final verdict. It is an experiment getting active people from these several communities together and we have to sense how they feel about it afterwards. Did they like it? Did they find each others' talks interesting? Will some collaborate or trade ideas more? Will there be further conferences with a thoughtfully constructed mix like this----I don't mean just an omnibus jumble---more interesting than that, more selective.

Maybe the experiment will fail! Maybe they will all go back to their separate specialized conference formats. We'll see.

But right now I see so many signs that the Zurich conference is working that I am feeling very hopeful and good about it.

I'm still wondering what Nicolai's talk will be about. Do you have a guess? I could not find any recent paper of his about "infinite dimensional symmetry", the Wheeler-DeWitt equation, or the FRW model of cosmology.

I have to get to bed, nearly midnight. Hope we can talk more in the morning.

 

[Fra]

Fra! take a look at Chamseddine's slides PDF. Gives some help understanding of how the Standard Model arises from Noncommutative Geometry.

I've had a little hard to adapt to the NCG way of thinking. It is interesting, and the concept of non-commutative coordinates is exactly what I EXPECT to get out of the process where spacetime and generally dimensionality is emergent. BUT, I the continuum context is still a big fog, it isn't helping me.

I personally see an interesting possible connection to real discrete models such as may causal set programs, continuum limits may be emergent for complex systems where the coordinates to not commute. But it's the logic of this I want to start with. If you consider the coordiates in each dimension as beeing indexed by more and more high density counters, defined from histories of other counter states. There is an order in which dimensions emerge, one by one, and it seems obvious that the information flow in this structures suggests that actual coordiate information is related, and not exactl commuting.

But it seems to me that this is taken as a starting point of NCG? This I have a problem with. Isn't it quite interesting to understand the origin of the non-commutativity?

Unless I miss something there is no answer to this, is there?

I admit that I at least my understanding is not satisfied with the apparent strategy of the NCG. It seems to be more an elaboration of possible mathematical structures, and see how it may or many not apply to physics. It now seems to have technical fits. But I don't at the moment see where the predictive value enters, unless the reason for WHY coordinates does not commute. Shouldn't we understand HOW they don't commute, in order to predict something, rather using a desired prediction to infer how they "must discommute".

So, I think NCG is interesting, and the connection ot SM is interesting, but I find not coherent reasoning in their method that I can get my brain to accept.

It seems like the causal set level or something in a similar spirit is where whatever LEADS to NCG should start?

/Fredrik

 

[marcus]

Last time I updated the list of available slides PDFs there were 28, let's see how many new ones have been posted. I think these 4:

Steinacker: Matrix models, noncommutative gauge theory and emergent geometry
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:steinacker.pdf

Wulkenhaar: Ward identities in matrix models arising from noncommutative geometry
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:zurich11-raimar.pdf

Litim: Renormalisation group and the Planck scale
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:litimethz.pdf

Craps: Cosmological singularities in string theory
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:craps.pdf

The talks we still don't have PDF for are these 6:

Bodendorfer: Towards Loop Quantum Supergravity
Hoppe: Fundamental Structures of M-brane Theory
Longo: Boundary Quantum Field Theory and Conformal Field Theory
Mukhanov: Massive Gravity
Nicolai: Infinite-dimensional symmetries and the Wheeler-DeWitt equation
Wise: 2-Group Representations and State Sum Modelshttp://www.conferences.itp.phys.ethz.ch/doku.php?id=qg11:programme
http://www-conference.slu.se/strings2011/programme_NEW.html
https://www.akademikonferens.se/list.jsf?conf=strings2011-S (the link to the Uppsala participants list has been fixed.)

 

[atyy]

Hi Atyy,

Wouldn't you agree that mere diversity is of itself not especially desirable. I think the organizers were aiming at an intelligent mix of people who are doing creative work (of different sorts) right now, in the present---and whose work and ideas could on the whole be potentially of use to the others. Like planning a lively party introducing new people to each other.

When I first saw the list of speakers, I didn't realize how well it was going to turn out. I only began to reaiize how well the mix was thought out when I saw the titles. And even then in many cases I had to look at the slides PDFs before I saw how some of the pieces fit together.

We don't know the final verdict. It is an experiment getting active people from these several communities together and we have to sense how they feel about it afterwards. Did they like it? Did they find each others' talks interesting? Will some collaborate or trade ideas more? Will there be further conferences with a thoughtfully constructed mix like this----I don't mean just an omnibus jumble---more interesting than that, more selective.

Maybe the experiment will fail! Maybe they will all go back to their separate specialized conference formats. We'll see.

But right now I see so many signs that the Zurich conference is working that I am feeling very hopeful and good about it.

I'm still wondering what Nicolai's talk will be about. Do you have a guess? I could not find any recent paper of his about "infinite dimensional symmetry", the Wheeler-DeWitt equation, or the FRW model of cosmology.

I have to get to bed, nearly midnight. Hope we can talk more in the morning.

But how could any of the top professionals in quantum gravity not already have been aware of most of these developments?

Nicolai was talking about something like http://arxiv.org/abs/0912.0854.

I just noticed that Raman Sundrum is now at the same university as Ted Jacobson, where Michael Levin also is. Strominger has been trying to connect to Jacobson's EFE from thermodynamics for quite a few years now, and the proposal of a generalized second law is http://arxiv.org/abs/hep-th/0203101" . Or consider that Smolin has just had a paper on higher spin gravity, and Simone Giombi is at the Perimeter. I would be very surprised if Freidel didn't know all about BCFW. Same with the non-commutative geometry stuff: Chamseddine has worked in gravity as topology, and supergravity. Steinacker has long explicitly related his stuff to IKKT and to Freidel and Livine's vision of group field theory. Asymptotic Safety builds on tools that Polchinski made major contribution to.

Yes, Zurich certainly had interesting stuff - especially since Baez was there to make up for his cousin's absence (ok, I don't understand any of his professional stuff, but his maths for dummys are among the best fun lectures I've heard) - but to think of it as an agenda setting experiment which would either succeed or fail seems a stretch. Much good stuff in basic science comes by organic growth, without committee design. (I should also add that much good stuff in basic science comes from applied science.) It's always been that way - the top people keep themselves informed - Bach studied the concertos of the "Italian school", and was keenly interested in new developments in the by then old art of organ building, and still tested some of the very early pianofortes. (Well, sometimes they don't - it was very important for Cooley and Tukey to rediscover the FFT!)

 

[marcus]

Atyy, the 2009 Nicolai paper you point to does not say "infinite dimensional symmetries" although it does say WdW equation and talks about minisuperspace modeling of cosmology.
I still don't have a clear idea of what Nicolai's talk is going to be about. How would you classify it---say using the rough categories I mentioned? String, General considerations that apply across the board, or its own sui generis category...? He is one of the organizers and he's giving the concluding talk of the conference---it is bound to have some relevance to how he sees the QG field.

You mention a bunch of private individual cross-overs and interconnections. Nice. To me what they help prove is that the "Quantum Theory and Gravitation" field is ready to have a conference.

A conference serves to define and establish a field of research. It gets the crossovers and interconnections out in the open.

It also breeds collaboration---people meet listen to each other in person and sense each other's drive/ability and see who might be someone they want to co-author with.

You seem to be saying "why have a conference? all this interconnection is already happening!" then why ever have any conferences at all? What social and field-defining functions do conferences perform? Why ever bother to have them?

I say the interconnections you mention are all the more reason to have a combined QG conference. It is an important part of the process that defines a research community.

 

[atyy]

Atyy, the 2009 Nicolai paper you point to does not say "infinite dimensional symmetries" although it does say WdW equation and talks about minisuperspace modeling of cosmology.

It's explained in the first few paragraphs.

 

[marcus]

It's explained in the first few paragraphs.

I see! Thanks, Atyy.

As a reminder of what we've been discussing, as I see it the Zurich QTG (Quantum Theory and Gravitation) conference is aimed at joining several potentially complementary approaches to QG in a coherent research community.
I don't mean that the goal is a single "theory" (some things called "theory" aren't even well-formulated testable theories yet ) but rather a combined community of researchers able on occasion to exchange ideas and engage in collaboration---co-author papers, trade postdocs etc.

So the idea of the Zurich conference is not mere diversity for its own sake. It is a particular (and potentially fertile) mix of people and QG approaches.

Here are posts #2 and #3 of this thread--positions taken which may have helped initiate discussion:

I'd be interested to hear any reasons to explain a contrary view, but off-hand I'd say that QG 11 is obviously a far more interesting conference. The key factor is that it is mixed, so we should look more carefully at the makeup.
http://www.conferences.itp.phys.ethz.ch/doku.php?id=qg11:programme
http://www-conference.slu.se/strings2011/programme_NEW.html
I think at this point, with a declining enthusiasm for string and the focus of string researchers tending to spread out into less specifically string-unification areas---QG in particular, that if you are organizing a conference you can get more interesting people to talk about more interesting stuff if you make it mixed.

It is just how it is IMHO. Many of the smart people are interested in what is going on in neighboring lines of research, not just string. So we are probably going to see more conferences like QG 11---that is more heterogeneity---in the future.

Of course it would be delightful to hear an argument to the contrary, if anybody can think one.

Well, I'm voting with my feet and going to the Quantum Theory and Gravitation conference in Zurich...

Today (23 June) John Barrett announced that the European Science Foundation has extended the QG-network charter through end 2011.
http://www.maths.nottingham.ac.uk/qg/Meetings.html
The ESF-QG (Quantum Geometry and Quantum Gravity) was originally mandated to run five years: around June 2006 through June 2011. It has been the main engine behind a series of schools, workshops combining various QG approaches, and this conference.

Updated list of Zurich slides PDFs that are available on line--there are 33 sets of slides so far:

Wulkenhaar: Ward identities in matrix models arising from noncommutative geometry
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:zurich11-raimar.pdf
Steinacker: Matrix models, noncommutative gauge theory and emergent geometry
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:steinacker.pdf
Speziale: Spin networks as twisted geometries
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:speziale.pdf
Shaposhnikov: Scale-invariant alternatives to general relativity
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:shaposhnikov.pdf NEW
Rovelli: Loop quantum gravity: the covariant dynamics
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:zurichrovelli.pdf
Reuter: Einstein-Cartan Theory and Asymptotic Safety
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:reuter.pdf
Reiterer: A class of gauges for the Einstein equations
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:reiterer.pdf
Oriti: Group field theory: a brief survey of recent developments
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:oriti.pdf
Morton: Extended Field Theories and Higher Gauge Theories
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:morton.pdf
Loll: Nonperturbative highlights on quantum gravity from CDT
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:loll.pdf
Litim: Renormalisation group and the Planck scale
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:litimethz.pdf
Lewandowski: Canonical LQG: soluble models and other advances
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:lqgrecentadvanceszurich.pdf
Lechner: Covariant and local deformations of quantum field theories
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:gandalf_lechner_-_zuerich_2011.pdf
Jacobson: How general is the generalized second law?
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:howgeneral-zurich.pdf
Hollands: Quantum field theory correlators on manifolds at very large and very short distances
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:zurich.hollands.pdf
Giulini: Very basic issues concerning quantum mechanics and gravitation
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:giulini_qg2011.pdf
Freidel: The principle of relative locality
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:freidel.pdf
Elvang: Symmetry constraints on the UV behavior of N=8 supergravity
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:countertermszurich-final.pdf
Dixon: Ultraviolet behavior of quantum (super)gravity through four loops
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:ld.ethz.qg.pdf
de Goursac: Renormalizability of noncommutative quantum field theories
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:goursac-zurich2011.pdf
Craps: Cosmological singularities in string theory
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:craps.pdf
Compere: The translation anomaly of asymptotically flat spacetimes
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:compere.pdf
Chamseddine: The Spectral Action
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:chamseddine.pdf
Bossard: Toward the consistency of N=8 supergravity as a quantum field theory
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:n_8consistency.pdf
Bodendorfer: Towards Loop Quantum Supergravity
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:bodendorfer.pdf
Blau: String Theory as a Theory of Quantum Gravity: a Status Report
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:zurichblau.pdf
Beisert: Symmetries and Integrability for Scattering Amplitudes in N=4 Super Yang-Mills Theory
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:beisert.pdf
Barrett: State sum models and the spectral action
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:rg-zurich-talk.pdf
Baez: Higher gauge theory, division algebras and superstrings
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:baez.susy.pdf
Bachas: The problem of localization of gravity
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:bachas.pdf
Ashtekar: Quantum Cosmology and the Very Early Universe
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:ashtekar.pdf
Arnlind: Poisson Algebraic Geometry and Matrix Regularizations
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:arnlind.pdf
Ambjorn: CDT, a quantum theory of geometry
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:ambjorn.pdf

Links to the QG11 (Zurich) and Strings 2011 (Uppsala) websites:

http://www.conferences.itp.phys.ethz.ch/doku.php?id=qg11:programme
http://www-conference.slu.se/strings2011/programme_NEW.html
https://www.akademikonferens.se/list.jsf?conf=strings2011-S The talks we still don't have PDF for are these 5:

Hoppe: Fundamental Structures of M-brane Theory
Longo: Boundary Quantum Field Theory and Conformal Field Theory
Mukhanov: Massive Gravity
Nicolai: Infinite-dimensional symmetries and the Wheeler-DeWitt equation
Wise: 2-Group Representations and State Sum Models

 

[marcus]

John Baez and others discussing the Zurich QTG conference at n-Cat Café:
http://golem.ph.utexas.edu/category/2011/04/quantum_theory_and_gravitation.html#c038517

Baez suggests also checking Morton's blog later in case he might have something on QTG:
http://theoreticalatlas.wordpress.com/
I didn't see anything. If you see any other blog reports, please post links!

...The talks we still don't have PDF for are these 5:

Hoppe: Fundamental Structures of M-brane Theory
Longo: Boundary Quantum Field Theory and Conformal Field Theory
Mukhanov: Massive Gravity
Nicolai: Infinite-dimensional symmetries and the Wheeler-DeWitt equation
Wise: 2-Group Representations and State Sum Models

It turns out Hoppe gave a blackboard talk (no PDF presumably) but one of the others was posted today. We now have Roberto Longo's slides:

Longo: Boundary Quantum Field Theory and Conformal Field Theory
http://www.conferences.itp.phys.ethz.ch/lib/exe/fetch.php?media=qg11:zurichlongo11.pdf

Part of Longo's presentation is about some joint work he did with Edward Witten. That reminds me to mention that several of the Zurich speakers (e.g. Beisert, Blau, Elvang...) are also among those giving invited talks at Strings 2011 next week in Uppsala.

Regarding the Uppsala conference, anyone with an interest in how things are going with the string program might want to take a look at the list of registered participants to see who is attending.
https://www.akademikonferens.se/list.jsf?conf=strings2011-S
Besides the 30-some people giving talks (who obviously have to attend!), I saw a dozen or so other well-known people, but missed quite a few one might have expected (e.g. Arkani-Hamed, Strominger, Giddings, Neitzke, Silverstein, Gubser, Bousso, Kachru, Kallosh, Randall, Sundrum, Arnlind, Bachas...) Do you get the same impression?
Registration is now closed but will re-open Monday at the door, so more may show up.

 

[marcus]

The opening talk of Strings 2011 by David Gross can be seen here:
http://media.medfarm.uu.se/flvplayer/strings2011/video1

The other talks can be watched live, as they are given. Just now I was watching the talk by Niklas Beisert.

To find the relevant links, go to the programme webpage.
http://www-conference.slu.se/strings2011/programme_NEW.html

The list of registered participants has 259 names:
https://www.akademikonferens.se/list.jsf?conf=strings2011-S

The quality of the sound and video is excellent IMO, at least by my standards.

Unfortunately Sweden time is 6 hours ahead of East Coast Usa time, and 9 hours ahead of Pacific (my time).

So for example Witten talks at 11 AM in the morning on Tuesday. Which means I would have to get up at 2AM tomorrow morning to hear the talk live. Or someone on the East coast would have to get up at 5AM. So watching most of the talks live is out of the question.

Presumably stored versions of the other talks will eventually be posted online in the same way as Gross's opening speech.

For now, six are so available. Besides Gross's there are:
Michael Green http://media.medfarm.uu.se/flvplayer/strings2011/video2
Thomas Klose http://media.medfarm.uu.se/flvplayer/strings2011/video3
Henrik Johansson http://media.medfarm.uu.se/flvplayer/strings2011/video4
Fabio Zwirner http://media.medfarm.uu.se/flvplayer/strings2011/video5
Niklas Beisert http://media.medfarm.uu.se/flvplayer/strings2011/video6

 

[marcus]

Henriette Elvang's review of scattering amplitudes (crisp well-organized fast-moving)
http://media.medfarm.uu.se/flvplayer/strings2011/video9

Witten's talk
http://media.medfarm.uu.se/flvplayer/strings2011/video10
The link did not work, probably because so many people are trying to watch his talk and there is a simple overload of the resources. Perhaps later.

By now they have put up video for a dozen or so, the links are consistently numbered in the order that the names appear in the programme:


David Gross
Michael Green
Thomas Klose
Henrik Johansson
Fabio Zwirner
Niklas Beisert
Sergio Cecotti
Dimitrios Tsimpis
Henriette Elvang
Edward Witten
Samson Shatashvili
Alexei Morozov

..., you have big names like Wilzcek, Verlinde and Linde with very tasty titled talks.

Judging from the title, Verlinde is giving the same talk (The Hidden Phase Space of Our Universe) that he gave at Perimeter last week on 22 June. It is certainly interesting despite or perhaps because on a divergent track from the rest of the conference.
Here is the Perimeter video:
http://pirsa.org/11060065/
The Hidden Phase Space of our Universe
Erik Verlinde
So there is no need to wait until Friday, when he gives the talk at Uppsala. One can watch it already on the Perimeter archive.

I too look forward to Wilczek's talk on Thursday. I think it will be another divergent . talk. As you say, the title is "tasty". His topic is three different BSM futures that could I suppose follow from, for instance, LHC results.

 

[unusualname]

The Hidden Phase Space of our Universe
Speaker(s): Erik Verlinde
Abstract: By combining insights from black holes and string theory we argue for the existence of a hidden phase space associated with an underlying fast dynamical system, which is largely invisible from a macroscopic point of view. The dynamical system is influenced by slow macroscopic observables, such as positions of objects. This leads to a collection of reaction forces, whose leading order Born Oppenheimer force is determined by the general principle that the phase space volume of the underlying system is preserved. We propose that this adiabatic force is responsible for inertia and gravity. This fact allows us to calculate the hidden phase space volume from the known laws of inertia and gravity. We find that in a cosmological setting the appearance of dark energy is naturally explained by the finite temperature of the underlying system. The adiabatic approximation that leads to the usual laws of inertia and gravity breaks down in the neighborhood of horizons. In this regime the reaction force degenerates into an entropic force, and the laws of inertia and gravity receive corrections due to thermal effects. A simple estimate of these effects leads to the conclusion that they coincide with observed phenomena attributed to dark matter.

Dark energy I think will have some not so spectacular explanation, maybe even like Verlinde is suggesting here, but wow, that's a pretty risky claim about dark matter. If supersymmetry is found at the LHC then many people expect dark matter to be neutralinos.

Still with the recent few millions euros of funding for Verlinde's programme I think this will develop pretty quickly, and we shouldn't have to wait more than a year or two for dismissal or support (if the LHC doesn't get there first)

 

[marcus]

Heres a link if anybody wants a list of the Strings 2011 talks for which videos are online.
http://media.medfarm.uu.se/flvplayer/strings2011/

There is usually no wait, and the quality is excellent!

At present videos of 21 talks are available.

To my way of thinking the most interesting and at the same time divergent talk of the conference will not be given at Uppsala until Friday 1 July, but has already been given at Perimeter Institute last week (22 June) and is also available in excellent video online:
Here is the Perimeter video:
http://pirsa.org/11060065/
The Hidden Phase Space of our Universe
Erik Verlinde

I'm not sure but I think Unusualname might agree with me. Unusual points out that Verlinde may be betting against low-energy Susy. The nice explanation of Dark Matter from Susy requires that supersymmetry appear at low energy so that it would be detected at CERN in the next couple of years. Suppose it is not (which I think is quite possible). This would make Verlinde's theory look good because he has a different idea of how effects attributed to Dark Matter might arise.

(I suspect he is wrong about DM. It already has too many different observed effects and its material existence is too well established. He says at the outset that his ideas about DM are speculative--but they are still very interesting.)

 

[unusualname]

Heres a link if anybody wants a list of the Strings 2011 talks for which videos are online.
http://media.medfarm.uu.se/flvplayer/strings2011/

There is usually no wait, and the quality is excellent!

At present videos of 21 talks are available.

To my way of thinking the most interesting and at the same time divergent talk of the conference will not be given at Uppsala until Friday 1 July, but has already been given at Perimeter Institute last week (22 June) and is also available in excellent video online:
Here is the Perimeter video:
http://pirsa.org/11060065/
The Hidden Phase Space of our Universe
Erik Verlinde

I'm not sure but I think Unusualname might agree with me. Unusual points out that Verlinde may be betting against low-energy Susy. The nice explanation of Dark Matter from Susy requires that supersymmetry appear at low energy so that it would be detected at CERN in the next couple of years. Suppose it is not (which I think is quite possible). This would make Verlinde's theory look good because he has a different idea of how effects attributed to Dark Matter might arise.

(I suspect he is wrong about DM. It already has too many different observed effects and its material existence is too well established. He says at the outset that his ideas about DM are speculative--but they are still very interesting.)

I haven't had a chance to view the Verlinde talk yet, but I applaud his bravado in claiming that even dark matter may have an entropic explanation.

If the LHC finds the Higgs boson at ~115-120Gev (or so) then that will really support the Minimal Supersymmetric Standard Model, which suggests dark matter is neutralinos.

I'm surprised Verlinde's talk is at a Strings conference, seems the string guys are loosening up a bit and allowing speculative non-stringy ideas at their showpiece annual conference!

 

[marcus]

...
I'm surprised Verlinde's talk is at a Strings conference, seems the string guys are loosening up a bit and allowing speculative non-stringy ideas at their showpiece annual conference!

They've GOT to!
Look at the numbers.

Annual first-time faculty hires (US and Canada) in HEP theory as a whole, and in string, averaged over 3 year periods

period                           1999-2001    2002-2004   2005-2007    2008-2010
annual HEP theory hires as a whole      18           24          23           13
annual string hires                      9            8           6            2

Registered participants in the annual conference (some years omitted for brevity)

Strings 2003 Kyoto     396
Strings 2005 Toronto   415
Strings 2007 Madrid    440
Strings 2009 Rome      450
Strings 2010 Texas A&M 193
Strings 2011 Uppsala   259

Number of recent string papers making the top fifty in the annual Spires HEP topcite list

year (some omitted for brev.)   2001    2003    2005    2007    2009    2010
recent work highly cited in year  12       6       2       1       1       0

A paper is counted as recent if it appeared in the previous five years. This gauges the quality/significance of current work by how other researchers receive it.

Links to sources here
https://www.physicsforums.com/showthread.php?p=3373453#post3373453

The program is losing perceived relevance. They have to "loosen up a bit", as you put it.

 

[unusualname]

yeah, but Strings is much harder than the other toy stuff, so it's no surprise if those numbers you quote are declining while we wait for some experimental support from the LHC.

I think it's inconceivable, if you look at the history of physics, that so many people in such prestigious academic positions, could be completely misled up the wrong path.

 

[marcus]

...
I think it's inconceivable, if you look at the history of physics, that so many people in such prestigious academic positions, could be completely misled up the wrong path.

Don't be too sure. And keep an eye on where the research interests of some of the best are tending.

 

[suprised]

I'm surprised Verlinde's talk is at a Strings conference, seems the string guys are loosening up a bit and allowing speculative non-stringy ideas at their showpiece annual conference!

"loosening up a bit and allowing"… you guys have a completely wrong perception of how things actually are! No one would mind, were it not that other people would be influenced by this desinformation. Quite oppositely, Erik's ideas _are_ related to string theory as they involve matrix theory. Just care to read the first sentence of the abstract of his talk at Perimeter:

" By combining insights from black holes and string theory we argue …."

And marcus, thanks for your tip! The professional scientists are just too grateful to get advice from recreational armchair experts!

 

[MTd2]

I think it's inconceivable, if you look at the history of physics, that so many people in such prestigious academic positions, could be completely misled up the wrong path.

Epicycles...

 

[marcus]

Heh heh. Don't forget Phlogiston.
Or the Aether.

A few posts back I mentioned the conference attendance figure for Strings 2011. It is actually 257 (see https://www.akademikonferens.se/list.jsf?conf=strings2011-S ) so I'll correct the table.

Registered participants in the annual conference (some years omitted for brevity)

Strings 2003 Kyoto     396
Strings 2005 Toronto   415
Strings 2007 Madrid    440
Strings 2009 Rome      450
Strings 2010 Texas A&M 193
Strings 2011 Uppsala   257

Here's the main video link:
http://media.medfarm.uu.se/flvplayer/strings2011/
David Gross's opening talk provided, I think, a good window on the state of things in the string program generally, possibly also the mood.
Gross-- http://media.medfarm.uu.se/flvplayer/strings2011/video1
Frank Wilczek gave an invited talk on "three ways beyond the standard model". None were stringy. He described his approach as "bottom up" and "zero-brane". Talked mostly about his first two topics: quantitative unification and axions. To stay within time he had treat the planned third topic (portals) lightly.
Wilczek-- http://media.medfarm.uu.se/flvplayer/strings2011/video24
Wilczeck made a special point of praising Fabio Zwirner's talk, the only talk at the conference he cited or recommended. It was also not a string theory talk, actually, but was about LHC results:
Zwirner-- http://media.medfarm.uu.se/flvplayer/strings2011/video5
Verlinde's talk is tomorrow. Here's the advance copy.
Verlinde-- http://pirsa.org/11060065/

 

[marcus]

Peter Woit had an interesting Update on Strings 2011 today
==quote==
Update: After looking at most of the talks online, the most remarkable thing about Strings 2011 is how little there is about string theory. One of the speakers, Chris Hull, started off his talk with the comment:

At lunch today one of the organizers was observing that my talk was unusual in being one of the few talks actually about string theory. It would be interesting to speculate on what that might mean about the state of the field, but it would be invidious to do so here.
​

One of the main themes of the conference so far has been study of mathematically interesting supersymmetric QFTs in 3,4,5 and 6 dimensions, often obtained from a specific class of 6d theories, which themselves remain poorly understood (what is known about them was reviewed by Greg Moore). Witten gave an overview of his work relating Khovanov homology and QFT, which involves a chain of various 6d, 5d, 4d, 3d and 2d QFTs. Nati Seiberg reviewed the technology used for constructing these theories on various special backgrounds, noting that this was all about “rigid” SUSY theories, with supergravity and string theory making no appearance.
==endquote==
http://www.math.columbia.edu/~woit/wordpress/?p=3811

One can always draw some connection between whatever and something studied in the string program. So presumably one can say that this or that is "string inspired" or "guided by insights from string" if it makes people feel good. As for instance Verlinde tactfully did in the introduction to his Perimeter talk.

Anyway here is the link to Chris Hull's talk which a Strings 2011 conference organizer described as one of the few talks that was actually about string theory.
Hull-- http://media.medfarm.uu.se/flvplayer/strings2011/video16