Lattice 2006, the big yearly conference on lattice gauge theory, is going on the week in Tucson. The program is here, and both plenary and parallel session talks are being posted. Georg von Hippel is blogging from the conference, his blog entries so far are here, here and here. One of the main topics is dynamical fermions, with a nice talk by Steven Sharpe. He discusses staggered fermions, which unfortunately come quadrupled with respect to what one wants, providing four “tastes” of fermions instead of a single one. The question then is whether one can get away with just taking the fourth root of the fermion determinant, which then makes the theory non-local. He concludes that this is not “Good” (i.e. having properties one would like even for non-zero lattice spacing), but it is not “Bad” (wrong continuum limit), it is just “Ugly” (for non-zero lattice spacing there are unphysical contributions, but these can be dealt with and made to go away as the lattice spacing goes to zero).
At the YITP in Stony Brook, a month-long workshop funded by Jim Simons on the String Landscape and the Swampland has begun this week. A schedule with links to audio of the talks is here. Today Cumrun Vafa is giving a talk on the beach about the Landscape and the Swampland.
The XXXIII International Conference on High Energy Physics (ICHEP), the big summer conference on high energy physics at which many HEP experimental groups announce their results, started yesterday in Moscow. Fermilab has a special web-page for abstracts from its experimental groups.
There’s a review of Not Even Wrong by John Horgan in the August issue of the British magazine Prospect, entitled Stringing Us Along. Yesterday a short interview and discussion involving me and Daniel Waldram, a string theorist from Imperial College, was recorded by the BBC. I hear it was broadcast today on their “Today” radio program. Not sure how it came out after editing, and I can’t really bear to listen to recordings of myself, but the discussion was perfectly polite, with no one calling anyone else names.
The August issue of Scientific American has an article about Alain Connes and his non-commutative geometry interpretation of the standard model. He continues to work on this topic, from what I hear most recently thinking about different versions of this idea that incorporate right-handed neutrinos. For some of his latest still quite speculative ideas about quantum field theory, see his recent lectures on Noncommutative Geometry and Physics, as well as other papers available at his web-site. In his version of the standard model the Higgs field has an unusual origin and one naturally gets a relation between the Higgs coupling and gauge couplings, but this is at some very high energy scale where the idea is that the use of non-commutative geometry will replace standard GUT ideas. To extract a prediction of the Higgs mass from this one has to make various assumptions, including a desert hypothesis (no new physics from 1 Tev up to the unification scale), so it’s still unclear to me how solid a prediction this really is. For an example of a recent paper about this issue, see one by Knecht and Schucker.
Update: A commenter points to the website of MG11, the Marcel Grossman meeting. Videos of the talks are available. Alejandro Satz is blogged from the conference.
WHAT IS WRONG with lattice gauge theorists that they choose to hold their one conference of the year in *TUCSON* during what’s is probably the hottest week of the year? Them boys need some talkin’ to….
On Today: Listen Again
check out 0854 “Everything you need to know about string theory”
What do you think the chatter will be in Moscow during the conference there this month about work about to begin at Cern? By the way, have you had time to review this month’s Cern Courier? TThere is an interesting article about string theory, “Testing times for String Theory”?
What results would need to be produced by Cern for you to reconsider your position on the plausibility of string theory? Would also like your observations on the work being mounted in the Arctic to test String Theory.
Jut waiting to see what happens next…
Radio clip is now at:
(0854 Everything you need to know about string theory.)
It will only be there for a week.
I just listened to the audio clip. Here is an executive summary:
PETER: String theory is 10 dimensional, but the world in 4 dimensional. There’s no obvious, useful way to make it 4 dimensional, so it’s a waste of time.
DANIEL WALDRAM: I don’t agree with Peter. I like string theory and think it is good.
(If only they had had a worthy adversary like Lubos arguing the case for S.T.)
That article appears to be several years old. It’s standard hype about “braneworld scenarios”. Such models can be constructed that would have observable effects at the LHC. But there’s no evidence for them, and string theory doesn’t predict anything about them.
I think I wrote a posting somewhere concerning the hype about “testing string theory” using the detectors in the Antartic ice. It’s just hype.
If these brane-world scenarios do work out and involve a gravity scale in the TeV region, if string theory is the right theory of quantum gravity, there should be solid experimental evidence for it, and of course that would change my mind. I think this is extremely unlikely (and so do most string theorists…).
If there is big news at ICHEP, it would be because some experiment is reporting something new. I haven’t heard of anything in particular.
Here’s a direct link to the audio (RealPlayer file)
A good interview Peter. It’s just a pity that the producers didn’t see fit to make it a little longer.
I liked the Today discussion. Always nice to hear the presenters struggling with something.
The BBC interview shows how string theorists take the fact that string theory is a failure, and then use that as a reason to continue trying. You have to admire their perseverance. (If it predicted anything, would they finally call it ‘boring’, and move on?)
Daniel’s point is that string theory is interesting, exciting and ‘beautiful’ because it can’t predict anything to help physics.
He then said that there is no real problem of suppression because people are totally free to do whatever they want (they merely lose grants, jobs, career prospects if they don’t follow mainstream).
11th Marcel Grossmann meeting on gravity and astrophysics was held in Berlin last week. For those who are interested, videos of plenary talks are available at http://www.icra.it/MG/mg11/ (go to publications/conference livestream.)
I’ve been there, it was extremely hot (35C+ most of the days), and not very exciting scientifically. But some talks were really nice.
JKG, thanks for the MG11 link. Ashtekar’s talk was an obvious one for me to watch (I just did.) Any other especially nice plenary talks you want to mention?
I think if you review the cerncourier again, you will find it is this month’s. I honestly don’t feel that it is at all dated, but thanks for your comments.
Now don’t go knocking good ol’ Tuscon. There’s lots of beautiful women there (especially in the ASU astrophysics department).
What’s the deal with this FermiLab search beyond the Standrad Model?
Researchers Pursue A Narrow Particle With Wide
Source: Northeastern University
Posted: July 30, 2006
Northeastern University researchers Pran Nath, Daniel
Feldman and Zuowei Liu have shown that the discovery
of a proposed particle, dubbed the Stueckelberg Z
prime, is possible utilizing the data being collected
in the CDF and DO experiments at the Fermilab
Tevatron. The Stueckelberg Z prime particle,
originally proposed by Boris Kors currently at CERN,
Geneva, Switzerland and Pran Nath at Northeastern
University in 2004, is so narrow that questions had
been raised as to whether or not it could be detected.
This new research, published in the July issue of
Physical Review Letters, confirms that it can. The
results are of importance because the discovery of
this particle would provide a clue to the nature of
physics beyond the Standard Model and a possible link
with string theory.
“It is exciting to know that the discovery of the
proposed particle at colliders is indeed possible,”
said Pran Nath, Matthews Distinguished University
Professor of Physics at Northeastern University.
“Physicists are always looking for what is next, what
will lie beyond the Standard Model. These findings
point us in the direction of those answers.”
Because of its extreme narrowness, the Stueckelberg Z
prime particle resembles the J/Psi (charmonium)
particle, whose simultaneous discovery in 1974 by
Burton Richter and Samuel Ting earned them the 1976
Nobel Prize in Physics. However, unlike the J/Psi
which is a bound state, the new particle is not a
bound state but a proposed new fundamental building
block of matter. What sets the new Z prime particle
apart from all others is the mechanism by which it
While in the Standard Model particles such as the W
and Z bosons gain mass by the Higgs phenomena, the new
Z prime particle gains mass by the Stueckelberg
mechanism proposed by the Swiss mathematician and
physicist Ernst Carl Gerlach Stueckelberg in 1938.
While the Stueckelberg mechanism arises naturally in
string theory, Kors and Nath were the first to
successfully utilize it in building a model of
“If the Stueckelberg Z prime particle were to be
discovered, it could signify a new kind of physics
altogether, a new regime so to speak,” said Nath. “The
prospect is quite exciting.”
=== end press release ===
JKG thanks for the MG11 link. Peter, did you watch the talks on string theory
at the MG11 link and what do you think?
I took a look at the program, but haven’t had the time or the interest to sit and listen to the talks. Too bad they don’t have transparencies on-line. I would be a bit curious to hear what Polyakov had to say.
If you go to http://www.miklei.de/mg11/ramData/mgm-arch-24-2.ram
and fast forward to ~ 51st minute you can go straight to Polyakov’s talk