Gerard ′t Hooft

 Name: ′t Hooft, Gerard

 Postal address: Spinoza Instituut,

 Leuvenlaan 4

 Postbus 80.195

 3508 TD
 Utrecht.

 Voorts verbonden aan:

 Institute for Theoretical
 Physics

 Universiteit Utrecht

 Leuvenlaan 4, 3584
 CC Utrecht

 Tel.: +31 30 253 5928

 Tel.  +31 30 253 1863

 Fax:  +31 30 253 5937

 e-mail: g.thooft@uu.nl

Warning: due to severe clogging of
this email post box, I can no longer guarantee that received messages will be
processed and/or answered.

 secretary: Wilma van Egmond, w.j.m.vanegmond@uu.nl

Discussing string theory with Gleb Arutyunov

Professor Theoretical Physics

Lectures:

Undergraduate and students in different fields:

"Ons Fysisch Wereldbeeld". For some PowerPoint slides of this lecture series (in Dutch) click here and here

Undergraduate lecture notes:

A short compilation of the most common Special Functions and Polynomials and their properties, emphasizing the most important features that they all have in common.

Advanced lecture notes:

Lecture notes Introduction to the Theory of Black Holes

Given in past years:

The lecture notes Introduction to General Relativity (in English) click here. These notes now also appeared as a book: Introduction to General Relativity, Rinton Press, Inc., Princeton NJ, ISBN 1-58949-000-2.
There is an ERRATUM referring to an equation in the end of these lectures (both in the book and in the notes of before Jan. 24,2001.)
A part 2 of these notes is in the making.

Topics in Theoretical Physics II - Group Theory (2008)

String Theory (2004, for 4th and 5th year students)

Lecture at Erice 2003, "Horizons" to be seen here. (static pictures of PowerPoint)

The Higgs Sector (Amsterdam, April 2003) (static pictures of PowerPoint)

Lecture notes of my lecture on "Quantum Mechanics and Determinism at the Planck Scale, to be seen here. (static pictures of PowerPoint)

Lectures given at the 5th WE Heraeus Summer School, Saalburg/Germany, September 1999, on "Monopoles, Instantons and Confinement", appeared as hep-th/0010225. (static pictures of PowerPoint)

Introduction to String Theory (version 14-05-04).

Memorial lecture Philippe Meyer (ENS, Paris, October 4, 2008)

Research interests:

Gauge theories in elementary particle physics.
This was the topic of the 1999 Nobel Prize. An idea was proposed by C.N. Yang and Robert Mills in 1954: they suggested that particles in the sub-atomic world might interact via fields that are similar to, but more general than electricity and magnetism. But, even though the interactions that had been registered in experiments showed some vague resemblance to the Yang-Mills equations, the details seemed to be all wrong. Attempts to perform accurate calculations were frustrated by infinite - hence meaningless - results. Together with my advisor then, and my co-Nobel-laureate now, M. Veltman, we found in 1970 how to renormalize the theory, and, more importantly, we identified the theories for which this works, and what conditions they must fulfil. One must, for instance, have a so-called Higgs-particle. These theories are now called gauge theories.

It was subsequently discovered that, indeed, the observed details of all known forces exactly agree with this picture. First it was found that the so-called weak force, in combination with the more familiar electro-magnetic one, is exactly described by a Yang-Mills theory. In 1973 it was concluded that also the strong force is a Yang-Mills theory. I was among the small number of people who were already convinced of this from early 1971. During the later 1970s, all pieces fell into place. Of all simple models describing the fundamental particles, one was standing out, the so-called `Standard Model'.
Gauge theories are the backbone of this Standard Model. But now it also became clear that this is much more than just a model: it is the Standard Theory. Great precision can be reached, though the practical difficulties in some sectors are still substantial, and it would be great if one could devise more powerful calculation techniques. Also, in spite of all its successes, the Standard Model, as it is formulated at present, shows deficiencies. It cannot be exactly right. Significant refinements are expected when the results of new experiments become known, hopefully during 2008 and subsequent years, when the European particle accelerator LHC becomes fully operational.

Quantum gravity and black holes .
The predominant force controlling large scale events in the Universe is the gravitational one. The physical and the mathematical nature of this force were put in an entirely new perspective by Albert Einstein. He noted that gravitation is rooted in geometric properties of space and time themselves. The equations he wrote down for this force show a remarkable resemblance with the gauge forces that control the sub-nuclear world as described in the previous paragraph, but there is one essential difference: if we investigate how individual sub-atomic particles would affect one another gravitationally, we find that the infinities are much worse, and renormalization fails here. Under normal circumstances, the gravitational force between sub-atomic particles is so weak that these difficulties are insignificant, but at extremely tiny distance scales, of the order of 10^-33cm, this force will become strong. We are tempted to believe that, at these tiny distance scales, the fabric of space and time is affected by quantum mechanical phenomena, but exactly how this happens is still very mysterious. One approach to this problem is to ask: under which circumstance is the gravitational force as strong as it ever can be? The answer to this is clear: at the horizon of a black hole. If we could understand the peculiar physical phenomena that one expects at the horizon of a black hole, and if we could find a meaningful description of its quantum mechanical laws, then perhaps this would open up new perspectives.

Fundamental aspects of quantum physics. I have deviating views on the physical interpretation of quantum theory, and its implications for Big Bang theories of the Universe. This topic has been expanded upon in recent publications, cf. "Quantum Gravity as a Dissipative Deterministic System", "The mathematical basis for deterministic quantum mechanics"; The Free-Will Postulate in Quantum Mechanics. (see my publication list).

To me, Nature is a big jig-saw puzzle, and I see it as my task to try to fit pieces of it together. Click and cut the pieces you see here from the screen and see how they fit, or: read more about it in my book: `Bouwstenen van de Schepping' (Prometheus/Bert Bakker, ISBN 90 351 1327 6) or its English version: `In Search of the Ultimate Building Blocks', Cambridge Univ. Press, Paperback 9.95 pounds, 14.95 US dollars, ISBN 0 521 578833; hardback 27.95 pounds, 39.95 US dollars, ISBN 0 521 550831) . In `Planetenbiljart', a personal view is described of the potentials of scientific and technological developments in the future. Which possibilities are there and are there things that will be impossible forever? Maybe you enjoy SF novels as much as I do, but don't mistake them for predictions of the future.

Important message for autograph collectors: Some people are afflicted with the desire to collect photographs and autographs of Nobel Prize winners. I am very flattered when I receive such requests, but I think I have done my share. I am sold out now. No more photographs or autographs, with apologies.

My reaction upon a letter that was sent to The New Scientist by a group of scientists who urge to establish new categories of Nobel Prizes. Later, I learned that the Nobel Committee itself reacted very much in the same spirit.

My laptop broke down and I had to buy a new one. All laptops in the shop came with Windows Vista. Now I knew that this program adds nothing of value to previous versions of Windows, and that it was reported to be very unstable. But, I thought, it cannot be that bad, and anyway, I had no choice. Indeed, it wasn't that bad: It was worse! It is so slow, and I never knew that so many things can go wrong and that a laptop could crash with such a frequency. Maybe it's time for Google to take over that market from Microsoft.

The English translation of "Planetenbiljart" has appeared. English title: "Playing with Planets" (World Scientific, Singapore). See http://www.worldscibooks.com/general/6702.html. The original text has been improved in many ways. Translation by my daughter Saskia.

For some new fractals obtained using PostScript and PovRay, see my Computer art gallery.

As illustrated by this photo, all cattle in the meadows of the Netherlands by law have to wear ear tags. My bicycle trip in the countryside inspired me to modify the bylaws of Constitution Law # 13 for 9491 Thooft's Constitution.

For alternative views concerning the question "what is science, and what isn't?", see this link

From January 2007: Chief Editor of Foundations of Physics, an International Journal devoted to the conceptual bases and fundamental theories of Modern Physics, Biophysics and Cosmology, Springer.

Special message to those who wish to mail to me their new revolutionary theories: Please first check your Baez index, and/or consult Warren Siegel.

Asteroid 9491 Thooft has its orbit between those of Mars and Jupiter. This asteroid was discovered March 25, 1971, by C.J. van Houten and I. van Houten-Groeneveld on Palomar Schmidt plates taken by T. Gehrels.
They are also the discoverers, in 1977, of asteroid 11779 Zernike, named after my grand-uncle Frits Zernike.

"for elucidating the quantum structure of electroweak interactions in physics."

Another "experiment" was recently reported in which paranormal signals were claimed to be observed. Probably the flaw is an incorrect handling of the statistics, where unintentional bias was difficult to exclude. I am prepared to challenge these and any other serious investigators with a bet. See here the conditions.

I am married to: A. A.Schik, MD, anesthesiologist, Arbo-arts (medical doctor for company personnel).
Two daughters:
Saskia A. Eisberg - 't Hooft. Studied political science in Amsterdam and Hofstra University. Formerly Senior Associate at Control Risks Group, Singapore, now living in Paris, and
Ellen M. 't Hooft. Veterinarian at Animed Veterinary Hospital, Shedfield, SO32 2JG, UK.
Some pictures of my family

An account of our investigations in elementary particle physics, translated in various languages (more to come soon):

My special greetings to visitor number 479709(since 25/10/99)
If this page looks messy it is because I only have access to an inferior Microsoft product to design it. My apologies.
Last revised: October 12, 2009..