# 't Hooft Birthday Party

1. Jul 16, 2006

### marcus

Renate Loll was co-organizer of a Gerard 't Hooft 60th birthday celebration Physics conference going on now on a pretty Dutch island

Today 15 July, Lee Smolin and Carlo Rovelli gave talks
Frank Wilczek was one of the speakers yesterday. The party lasts three days 14-16 July.

http://www1.phys.uu.nl/gerard60/program/

I think the usual name for this kind of conference is "[name]FEST"

like this one would be called "'t HOOFT FEST"
===============

Renate gave the opening (welcome) talk yesterday.
Later Frank Wilczek gave a talk about 3 candidates for dark matter.
I guess 't Hooft is pretty interested in Quantum Gravity because several of the talks today seem to be QG.
Tomorrow talks include some by famous string personages and by cosmologists:
David Gross, Leonard Susskind, Andrei Linde, Lawrence Krauss
there is a PDF printable version of the program incase anyone is interested.

http://www1.phys.uu.nl/gerard60/program/program-full.pdf

the 't Hooft-fest venue is a beach hotel
one of the events is a barbecue, another is a picnic at the lighthouse.

Last edited: Jul 16, 2006
2. Jul 16, 2006

### Careful

**
I guess 't Hooft is pretty interested in Quantum Gravity because several of the talks today seem to be QG. **

No kidding, he is at least writing about this since the beginning of the eighties; he has done some very important work (with Roman Jackiw) in 2+1 gravity'' coupled to point particles. Since 1996 he is gradually publishing about deterministic QM as (the ?) solution to the damn problem'' (as I call it).

Careful

3. Jul 16, 2006

### Kalimaa23

Aah, I think that maybe explains where my thesis advisor went. He mumbled something about being abroad this week...

4. Jul 16, 2006

### marcus

the guy has a sense of humor, Dimitri
isnt it just a little offshore island with a beach where you can go for holiday?

5. Jul 16, 2006

Staff Emeritus
I tried to search for 't Hooft on arxiv just now and it couldn't interpret his name. I tried 't Hooft and they thought I meant Hooft and found no matches. So I put quotes around, "'t Hooft" and they apparently searched for "t AND Hooft". Dumb system! Does anybody know how to do this?

6. Jul 16, 2006

### neutrino

http://arxiv.org/find/quant-ph/1/au:+Hooft_G/0/1/0/all/0/1

Here's a list, and I'm not sure if it's exhaustive. I searched for his deterministic QM paper and then clicked on his name to arrive at the above page.

7. Jul 16, 2006

### Careful

I thought you had to type in Hooft.

Careful

8. Jul 16, 2006

Staff Emeritus
Right, I finally tried that and it worked. We seem to be farther from the Singularity than I thought! Human brains have "grandmother cells", one per important known face, for instant recognition, but arxiv can't find a Nobel winning physicst when his name is spelled correctly!

Do you think he is serious with this mapping to the classical system with the huge "gauge" group? It seems at first sight more of a stunt; he admits it won't work for massive fermions, and hasn't tried it on anything much bigger than the harmonic oscillator, which is like a spin foam guy being restricted to 1+1 spacetime.

9. Jul 16, 2006

### marcus

however this link gives 51 papers
http://arxiv.org/find/grp_physics/1/au:+Hooft/0/1/0/all/0/1

.../find/quant-ph/1...

the alternative link, which gets more papers, has
.../find/grp_physics/1...

what Careful says is quite right, the form of the name to use is simply Hooft
but when one uses the search engine one must also select the area
and one should specify "all" physics to get the most hits.

Last edited: Jul 16, 2006
10. Jul 16, 2006

### neutrino

Noted. Thanks, marcus.

Also, he ('t Hooft) hasn't stuck to a single name; you can see a few G.W.'t Hooft's, too.

11. Jul 16, 2006

### Careful

**
Do you think he is serious with this mapping to the classical system with the huge "gauge" group? **

** It seems at first sight more of a stunt; he admits it won't work for massive fermions **

The particular ansatz he makes for the massless case does not work for the massive one. All this says is that he does not know the beables for -say- electrons at the moment which is not a shame since that is a partially open problem with a very long history.

**and hasn't tried it on anything much bigger than the harmonic oscillator, which is like a spin foam guy being restricted to 1+1 spacetime. **

I cannot disagree more with what you say (in many ways). Anyone who knows quantum mechanics and the old theorems concerning the possibility of deterministic interpretations knows that getting out the harmonic oscillator requires a very different way of thinking about reality. The reason is that the excited states of the harmonic oscillator are known to be non-classical in the sense that the Wigner density becomes negative. Therefore, it is useful to construct weird'' toy models which are able to surpass this - as well as looking at quantization in ways which are not immediatly what one would like it to be (such as the quantum constraint idea applied to classical quantum systems to make the Hamiltonian positive). Many realists would perhaps even doubt that one needs to find all states of the harmonic oscillator since we do not measure them separately anyway.

Concerning the spinfoam analogy, they will face similar problems as realists a la 't Hooft do now in the future (when they have to say what particles are, and how the standard model has to emerge). More about that later, bedtime now.

Careful

12. Jul 16, 2006

Staff Emeritus
Thanks for the context, careful. I'll take another look at the 2004 paper.

13. Jul 17, 2006

### arivero

Outside his recent work on quant-ph, I have around the table a review paper on the instanton thing, http://arxiv.org/abs/hep-th/9903189 (It is not a widely quoted paper; I think I come to it via a recent short note of Tornqvist, hep-ph/0606041)

Last edited: Jul 17, 2006
14. Jul 18, 2006

### john baez

If you're trying to find 't Hooft's most important papers, don't bother looking on the arXiv. He's basically a pre-arXiv guy.

15. Jul 18, 2006

Staff Emeritus
The stuff I've found seems to be mostly talks and other summaries of his off-arxiv papers. But for my light-minded purposes that's enough for the moment.

16. Jul 18, 2006

### ccdantas

17. Jul 18, 2006

### ccdantas

Ops, someone named Hooft, Emilie E. E. also entered in the search I mentioned, but it seems to be a minor intrusion.

Christine

18. Jul 18, 2006