23rd Solvay Conference in Physics - Solvay Institutes

Brussels, 1 December 2005
Press conference
23 rd Solvay Conference in Physics
“The Quantum Structure of Space and Time”
Brussels, 1 December 2005
EMBARGO 1 DECEMBER 2005 12:00
WHAT?
WHO?
Opening of the 23 rd Solvay Conference in Physics
Marc HENNEAUX (Solvay Institutes and ULB, BE)
David GROSS, 2004 Nobel Laureate (Kavli Institute, USA)
Michael ATIYAH, 1966 Fields Medal (University of Edinburgh, UK)
Robert BROUT, 2004 Wolf Prize (ULB, BE)
François ENGLERT, 2004 Wolf Prize (ULB, BE)
Murray GELL‐MANN, 1969 Nobel Laureate (Santa Fe Institute, USA)
Gerard ’t HOOFT, 1999 Nobel Laureate (Spinoza Institute, NL)
Steven WEINBERG, 1979 Nobel Laureate (University of Texas at Austin, USA)
Frank WILCZEK, 2004 Nobel Laureate (MIT, USA)
Shing‐Tung YAU, 1982 Fields Medal (Harvard University, USA)
WHERE? Hôtel Métropole, Place de Brouckère, 1000 Brussels
The 23 rd Solvay Conference in Physics will take place in Brussels, from December 1 through
December 3. Entitled “The Quantum Structure of Space and Time”, the Conference will address
one of the greatest challenges of present‐day fundamental physics i.e. to reconcile the two
conceptual revolutions of the 20 th century: Einstein general theory of relativity and quantum
mechanics.
The Conference will be chaired by David Gross, 2004 Nobel Laureate in physics. Following the
tradition initiated by H.A. Lorentz and continued by the other distinguished physicists who
chaired the Solvay Conferences after him (P. Langevin, W.L. Bragg, R. Oppenheimer, L. Van Hove
to name a few), a large part of the 23 rd Conference will be devoted to discussions.

By bringing regularly to Brussels the leading scientists working in physics and chemistry, the
renowned “Conseils Solvay” have shaped – and still shape – modern science. There is no other
conference series in the world with a comparable record.
In the presence of His Royal Highness Prince Philippe
On Thursday December 1, the opening session of this Conference will be held on the historical
importance of the Solvay Conferences, from 8:30 till 10:30. It will be presented by the renowned
historian of science Peter Galison (Harvard) in the presence of His Royal Highness Prince Philippe.
If you wish to attend, please tick the corresponding box in the enclosed confirmation of attendance
form.
Lunch with the participants
After the press conference (His Royal Highness will not be present during the press conference),
you can have lunch with the participants (13:00 – 14:00). A brief presentation of each of them will
be sent later but let us already mention the presence of Brian Greene (author of “The Elegant
Universe”), Thibault Damour, Gabriele Veneziano etc. If you are interested, please let us know.
Public event – December 4
For the very first time in its history, the Solvay Conference will open its doors to the public. A halfday
event will take place in Brussels on 4 December. During this afternoon, the public will have
the possibility to follow talks given by famous scientists, to meet Nobel Prize Laureates and to ask
their questions about the Universe. People can register and ask their questions through the
website: www.europa.eu.int/solvay2005
Media Contacts
► Michel Claessens, Press and information officer, Research DG, European Commission, Tel:
+32.2.295 99 71, Fax: +32.2.295 82 20, E‐Mail: Michel.Claessens@cec.eu.int
► Isabelle Juif, Conference organiser, Solvay Institutes, Tel: +32.2.650 54 23, Fax: +32.2.650.50.28,
E‐Mail: Isabelle.Juif@ulb.ac.be

PRESS PACK
I. The 23 rd Solvay Conference in Physics
a. Scientific background
b. List of participants in the Conference
c. Short biography of the speakers at the press conference
d. Short presentation of the other invited participants
e. Programme of the Conference
II. The Solvay Conference public event (Sunday December 4, 2005)
a. General information
b. Programme of the event
c. Poster of the event
III. The Solvay Conferences in Physics – a brief history
IV. The Solvay Institutes
a. Short presentation
b. Solvay Scientific Committee for Physics
c. Sponsors

I. ‐a‐
The 23 rd Solvay Conference in Physics
“The Quantum Structure of Space and Time”
Scientific background
What will be the central scientific issues under focus at the 23 rd Solvay Conference? The
text below gives information on those questions. [Background information in French and
Dutch also enclosed.]
Quantum gravity
Two major achievements of early 20 th century physics were the development of
quantum mechanics and the discovery by Einstein of the theory of general relativity. The
former describes the laws of physics at the smallest scales while the latter is the classical
theory of gravity, which dominates physics at the largest scales. Both theories have been
checked in numerous settings and with an astonishing accuracy. In view of this, it is
highly surprising that both theories are found to be mutually incompatible: all attempts to
quantize gravity along the lines that proved successful for the other forces lead to
insurmountable difficulties (e.g. infinite probabilities).
Reconciling general relativity with quantum mechanics is a challenge for the 21 st
century. A very promising avenue is string theory, in which the fundamental quanta are
not point particles but extended objects. String theory realizes the old dream of Einstein of
unifying all the forces and matter. Other interesting approaches to quantum gravity exist.
All these indicate that our concepts of space and time (including the very notion of
spacetime dimension) will have to be dramatically revised at the microscopic level.
Quantum mechanics will most likely also need important revisions.
Black holes, cosmology & singularities
General relativity predicts singularities in the structure of spacetime, i.e., places
where the spacetime geometry is infinitely distorted (infinite dilation of time, infinite
streching or infinite squeezing of spatial distances). This occurs inside black holes –
objects whose gravitational attraction is so strong that nothing, not even light, can escape
from them – and in the past evolution of the universe itself (“big bang”).
Singularities are clearly unphysical objects. Their prediction by the theory indicates a
limitation of (non quantum) general relativity. It is expected that singularities will be
smoothed out, i.e., made regular, by quantum effects. Studying singularities will therefore
provide important clues to quantum gravity and, in addition, will deepen our
understanding of black holes as well as of our universe in the very first moments of its
history.
Mathematical aspects
Gravity and mathematics have had close and fruitful ties since the Newtonian times.
There are many indications that quantum gravity will require new mathematics that do
not exist yet. The ties between theoretical physics and mathematics will thus deepen
further in the future and continue to bring fundamental developments in both physics and
mathematics.

First Name NAME Institution
1. Nima ARKANI‐HAMED Harvard University
I. ‐b‐
23 rd Solvay Conference in Physics
The Quantum Structure of Space and Time
2. Abhay ASHTEKAR Pennsylvania State University
3. Michael ATIYAH University of Edinburgh 1966 Fields Medal
4. Constantin BACHAS Ecole Normale Supérieure (Paris)
5. Tom BANKS Rutgers University
6. Lars BRINK Chalmers University of Technology and Göteborg University
7. Robert BROUT Université Libre de Bruxelles 2004 Wolf Prize
8. Claudio BUNSTER Centro de Estudios Científicos (Valdivia)
9. Curtis CALLAN Princeton Univesity
10. Thibault DAMOUR Institut des Hautes Etudes Scientifiques (Paris)
11. Jan DE BOER University of Amsterdam
12. Bernard DE WIT University of Utrecht
13. Robbert DIJKGRAAF University of Amsterdam
14. Michael R. DOUGLAS Rutgers University
15. Georgi DVALI New York University
16. François ENGLERT Université Libre de Bruxelles 2004 Wolf Prize
17. Ludwig FADDEEV Steklov Institute of Mathematics, St Petersburg
18. Pierre FAYET Ecole Normale Supérieure
19. Willy FISCHLER University of Texas at Austin
20. Peter GALISON Harvard University
21. Murray GELL‐MANN Santa Fe Institute 1969 Nobel Prize in Physics
22. Gary W. GIBBONS University of Cambridge

23. Michael B. GREEN University of Cambridge
24. Brian R. GREENE Columbia University
I. ‐b‐
23 rd Solvay Conference in Physics
The Quantum Structure of Space and Time
25. David GROSS Kavli Institute & University of California at Santa Barbara 2004 Nobel Prize in Physics
26. Alan GUTH Massachusetts Institute of Technology
27. Jim HARTLE University of California at Santa Barbara
28. Jeffrey HARVEY Enrico Fermi Institute (Chicago)
29. Gary HOROWITZ University of California at Santa Barbara
30. Bernard JULIA Ecole Normale Supérieure (Paris)
31. Shamit KACHRU Stanford University
32. Renata KALLOSH Stanford University
33. Elias KIRITISIS Ecole Polytechnique (Paris)
34. Igor KLEBANOV Princeton University
35. Andrei LINDE Stanford University
36. Dieter LÜST Max‐Planck‐Institut für Physik (Munich)
37. Juan MALDACENA Institute for Advanced Study (Princeton)
38. Nikita NEKRASOV Institut des Hautes Etudes Scientifiques (Paris)
39. Herman NICOLAI Max‐Panck‐Institut für Gravitationsphysik (Potsdam)
40. Hirosi OOGURI California Institute of Technology
41. Joseph POLCHINSKI Kavli Institute & University of California at Santa Barbara
42. Alexander POLYAKOV Princeton University
43. Eliezer RABINOVICI The Hebrew University (Jerusalem)
44. Pierre RAMOND University of Florida at Gainesville
45. Lisa RANDALL Harvard University

I. ‐b‐
23 rd Solvay Conference in Physics
The Quantum Structure of Space and Time
46. Valery RUBAKOV Inst. for Nuclear Research (Moscow)
47. John SCHWARZ California Institute of Technology
48. Nathan SEIBERG Institute for Advanced Study (Princeton)
49. Ashoke SEN Harish‐Chandra Research Institute (India)
50. Stephen SHENKER Stanford University
51. Eva SILVERSTEIN Stanford University
52. Paul J. STEINHARDT Princeton University
53. Andrew STROMINGER Harvard University
54. Gerard ’T HOOFT Spinoza Instituut (Utrecht) 1999 Nobel Prize in Physics
55. Neil TUROK University of Cambridge
56. Gabriele VENEZIANO Collège de France (Paris)
57. Steven WEINBERG University of Texas at Austin 1979 Nobel Prize in Physics
58. Frank WILCZEK Massachusetts Institute of Technology 2004 Nobel Prize in Physics
59. Paul WINDEY Université Pierre et Marie Curie (Pais)
60. Shing‐Tung YAU Harvard University 1982 Fields Medal

I. ‐c‐
The 23 rd Solvay Conference on Physics
“The Quantum Structure of Space and Time”
Short biography of the speakers at the press conference

I. ‐c‐
David Gross
David Gross is the chair of the 23 rd Solvay Conference
on Physics. He is Professor of Physics at the
University of California at Santa Barbara and
Director of the Kavli Institute for Theoretical Physics.
In 2004, he obtained the Nobel Prize with David
Politzer and Frank Wilczek ʺfor the discovery of
asymptotic freedom in the theory of the strong
interactionʺ.
David Gross is also member of the Solvay Scientific
Committee for Physics.
Press release from the Nobel Foundation (2004):
A ʹcolourfulʹ discovery in the world of quarks
What are the smallest building blocks in Nature? How do these particles build up everything we
see around us? What forces act in Nature and how do they actually function? This yearʹs Nobel
Prize in Physics deals with these fundamental questions, problems that occupied physicists
throughout the 20th century and still challenge both theoreticians and experimentalists working
at the major particle accelerators.
David Gross, David Politzer and Frank Wilczek have made an important theoretical
discovery concerning the strong force, or the ʹcolour forceʹ as it is also called. The strong force is
the one that is dominant in the atomic nucleus, acting between the quarks inside the proton and
the neutron. What this yearʹs Laureates discovered was something that, at first sight, seemed
completely contradictory. The interpretation of their mathematical result was that the closer the
quarks are to each other, the weaker is the ʹcolour chargeʹ. When the quarks are really close to each
other, the force is so weak that they behave almost as free particles. This phenomenon is called
”asymptotic freedom”. The converse is true when the quarks move apart: the force becomes
stronger when the distance increases. This property may be compared to a rubber band. The more
the band is stretched, the stronger the force.
This discovery was expressed in 1973 in an elegant mathematical framework that led to a
completely new theory, Quantum ChromoDynamics, QCD. This theory was an important
contribution to the Standard Model, the theory that describes all physics connected with the
electromagnetic force (which acts between charged particles), the weak force (which is important
for the sunʹs energy production) and the strong force (which acts between quarks). With the aid of
QCD physicists can at last explain why quarks only behave as free particles at extremely high
energies. In the proton and the neutron they always occur in triplets.
Thanks to their discovery, David Gross, David Politzer and Frank Wilczek have brought physics
one step closer to fulfilling a grand dream, to formulate a unified theory comprising gravity as
well – a theory for everything.
More information at http://nobelprize.org/physics/laureates/2004/gross‐autobio.html
http://www.kitp.ucsb.edu/David_Gross_Bio.pdf

I. ‐c‐
Sir Michael Atiyah
Michael Atiyah is currently an Honorary Professor at
the University of Edinburgh. He received the
Fields Medal in 1966 and the Abel Prize in 2004.
His current work involves mathematical physics
and the relationship between geometry and particle
physics.
Biographical sketch taken from http://www.kitp.ucsb.edu/activities/public/auto/?id=356:
Michael Atiyah received both his BA and Ph.D.(1955) from Trinity College, Cambridge, England.
He held postdoctoral appointments at Cambridge and the Institute for Advanced Study. He
arrived in Oxford in 1961 as a Reader and then from 1963 to 1969 he held the Savilian Chair of
Geometry. He spent 3 years as Professor at the Institute for Advanced Study before returning t o
Oxford as a Royal Society Research Professor. In 1990 he became Master of Trinity College and
the first Director of the Newton Institute for Mathematical Studies in Cambridge. He retired from
these positions in 1997 and 1996 respectively. Professor Atiyah is currently an Honorary
Professor at the University of Edinburgh.
Atiyah has made many outstanding and fundamental mathematical contributions, especially in
areas involving interactions between geometry, topology and analysis. In collaboration with
Hirzebruch he pioneered the development of K‐theory, which is now crucial to the solution of
many important mathematical problems. His celebrated ʺindex theoremʺ with Singer led to new
connections in Differential geometry, topology and analysis. It has become an important tool in
theoretical physics. Many of the great results in 4‐manifold geometry rely on mathematical
theories in which he made foundational contributions. He has been very influential in bringing
the ideas of theoretical physicists to the attention of mathematicians and vice versa. For these and
other contributions he received numerous awards including the Fields Medal (1966), Royal Medal
(1968), De Morgan Medal (1980), King Faisal Prize (1987), the Copley Medal (1988) and the
Abel Prize in 2004. He was Knighted in 1983 and made a member of the Order of Merit in 1992.
He has been elected to the national academies of about 20 nations and received honorary degrees
from over 30 universities. Professor Atiyah served as President of the London Mathematical
Society (1974‐1976) and President of the Royal Society (1990‐1995) and is to become President of
the Royal Society of Edinburgh in October 2005. He also served as President of the Pugwash
Conferences (1997‐2002), an international organization dedicated to ʺreducing the danger of
armed conflict and seeking cooperative solutions for Global problems.ʺ
See also:
http://www‐groups.dcs.st‐and.ac.uk/~history/Mathematicians/Atiyah.html
http://www.fields.utoronto.ca/aboutus/jcfields/fields_medal.html
http://www.abelprisen.no/en/

I. ‐c‐
Robert Brout
Robert Brout is Honorary Professor at the Université
Libre de Bruxelles and Honorary Member of the
International Solvay Institutes. In 2004, he received the
Wolf Prize with François Englert and Peter Higgs for
“for pioneering work that has led to the insight of mass
generation, whenever a local gauge symmetry is
realized asymmetrically in the world of sub‐atomic
particles.”
From the press release of the Wolf Foundation:
Four fundamental forces are presently known. Two of them have a long range: electromagnetism
and gravity. Weak interactions have a short range, the composite hadronic‐nuclear forces are also
short‐ranged although color interactions among their constituents, the quarks, grow with
distance. The carriers of the interactions are themselves particles ‐‐ gauge particles. They have
zero mass when the forces have a long range. Such is the photon. They are massive, when the
forces have a short range. Electromagnetic interactions are very successfully described by a
theory, which has a very large degree of symmetry, a local symmetry called gauge symmetry. On
the one hand, it seemed that gauge symmetry necessarily implied that gauge particles have zero
mass; on the other, in the absence of a local gauge symmetry, the weak and hadronic short‐ranged
interactions were ill defined.
Professor Robert Brout, in collaboration with Professors Francois Englert and Peter W. Higgs,
have discovered how mass can be generated for gauge particles in the presence of a local abelian
and non‐abelian gauge symmetry. This was demonstrated by them, both classically and quantum
mechanically, successfully avoiding theorems initiated by J. Goldstone while indication that the
theory would remain well defined (renormalizable). Similar ideas have been developed in the
domain of condensed matter physics.
The work has deeply shaped the understanding of the fundamental interactions. It has allowed to
unify the long‐range electromagnetic forces with the short‐range weak ones. This was manifested
in the works of Glashow, Salam and Weinberg, determining the laws of the electro‐weak forces.
The discovery of Brout, Englert and Higgs, was essential to the proof of G. ‘t Hooft that the theory
with massive gauge particles is well defined; and subsequent calculations in that theory, verified
experimentally, culminating in the discovery of the massive W and Z particles. Mass generation
has been the cornerstone of many key theoretical results, including cosmology at high temperature
and density, grand unified theories and the possible realization of the Dirac monopole. Mass
generation is independent of the detailed short‐distance physics. It could be driven, among others,
by an elementary scalar, or by an effective composite scalar. Near future experiments are
constructed to shed light on this fundamental question. The above indicates the far‐ reaching
fundamental nature of the Brout‐Englert‐Higgs contribution.
See also: http://www.wolffund.org.il/main.asp

I. ‐c‐
François Englert
François Englert is Honorary Professor at the Université
Libre de Bruxelles and Honorary Member of the
International Solvay Institutes. In 2004, he received the
Wolf Prize with Robert Brout and Peter Higgs for “for
pioneering work that has led to the insight of mass
generation, whenever a local gauge symmetry is
realized asymmetrically in the world of sub‐atomic
particles.”
From the press release of the Wolf Foundation:
Four fundamental forces are presently known. Two of them have a long range: electromagnetism
and gravity. Weak interactions have a short range, the composite hadronic‐nuclear forces are also
short‐ranged although color interactions among their constituents, the quarks, grow with
distance. The carriers of the interactions are themselves particles ‐‐ gauge particles. They have
zero mass when the forces have a long range. Such is the photon. They are massive, when the
forces have a short range. Electromagnetic interactions are very successfully described by a
theory, which has a very large degree of symmetry, a local symmetry called gauge symmetry. On
the one hand, it seemed that gauge symmetry necessarily implied that gauge particles have zero
mass; on the other, in the absence of a local gauge symmetry, the weak and hadronic short‐ranged
interactions were ill defined.
Professor Robert Brout, in collaboration with Professors Francois Englert and Peter W. Higgs,
have discovered how mass can be generated for gauge particles in the presence of a local abelian
and non‐abelian gauge symmetry. This was demonstrated by them, both classically and quantum
mechanically, successfully avoiding theorems initiated by J. Goldstone while indication that the
theory would remain well defined (renormalizable). Similar ideas have been developed in the
domain of condensed matter physics.
The work has deeply shaped the understanding of the fundamental interactions. It has allowed to
unify the long‐range electromagnetic forces with the short‐range weak ones. This was manifested
in the works of Glashow, Salam and Weinberg, determining the laws of the electro‐weak forces.
The discovery of Brout, Englert and Higgs, was essential to the proof of G. ‘t Hooft that the theory
with massive gauge particles is well defined; and subsequent calculations in that theory, verified
experimentally, culminating in the discovery of the massive W and Z particles. Mass generation
has been the cornerstone of many key theoretical results, including cosmology at high temperature
and density, grand unified theories and the possible realization of the Dirac monopole. Mass
generation is independent of the detailed short‐distance physics. It could be driven, among others,
by an elementary scalar, or by an effective composite scalar. Near future experiments are
constructed to shed light on this fundamental question. The above indicates the far‐ reaching
fundamental nature of the Brout‐Englert‐Higgs contribution.
See also: http://www.wolffund.org.il/main.asp

I. ‐c‐
Murray Gell‐Mann
Murray Gell‐Mann is Professor Emeritus at the
Californian Institute of Technology. He is a
Distinguished Fellow at the Santa Fe Institute. In
1969, he received the Nobel Prize ʺfor his
contributions and discoveries concerning the
classification of elementary particles and their
interactionsʺ
Biography taken from http://www.santafe.edu/sfi/People/mgm/mgmbio.html
(Please follow the above link for the full text)
Murray Gell‐Mann is a Distinguished Fellow of the Santa Fe Institute, and author of the popular
science book, The Quark and the Jaguar, Adventures in the Simple and the Complex. In
1969, Professor Gell‐Mann received the Nobel Prize in physics for his work on the theory of
elementary particles. Professor Gell‐Mannʹs ʺeightfold wayʺ theory brought order to the chaos
created by the discovery of some 100 particles in the atomʹs nucleus. Then he found that all of
those particles, including the neutron and proton, are composed of fundamental building blocks
that he named ʺquarks.ʺ The quarks are permanently confined by forces coming from the
exchange of ʺgluons.ʺ He and others later constructed the quantum field theory of quarks and
gluons, called ʺquantum chromodynamics,ʺ which seems to account for all the nuclear particles
and their strong interactions.
Besides being a Nobel laureate, Professor Gell‐Mann has received the Ernest O. Lawrence
Memorial Award of the Atomic Energy Commission, the Franklin Medal of the Franklin
Institute, the Research Corporation Award, and the John J. Carty medal of the National Academy
of Sciences. He has been awarded honorary doctoral degrees from many institutions, including
Yale University, the University of Chicago, the University of Turin, Italy, and Cambridge and
Oxford Universities. In 1988 he was listed on the United Nations Environmental Program Roll of
Honor for Environmental Achievement (the Global 500). He also shared the 1989 Erice ʺScience
For Peaceʺ Prize. In 1994 he received an honorary Doctorate of Natural Resources from the
University of Florida.
[...] Although a theoretical physicist, Professor Gell‐Mannʹs interests extend to many other
subjects, including natural history, historical linguistics, archaeology, history, depth psychology,
and creative thinking, all subjects connected with biological evolution, cultural evolution, and
learning and thinking. He is also concerned about policy matters related to world environmental
quality (including conservation of biological diversity), restraint in population growth,
sustainable economic development, and stability of the world political system. His recent research
at the Santa Fe Institute has focused on the subject of complex adaptive systems, which brings all
these areas of study together.
See also : http://nobelprize.org/physics/laureates/1969/press.html

I. ‐c‐
Gerard ‘t Hooft
Gerard ’t Hooft is Professor of Physics at the University
of Utrecht. In 1999, he received the Nobel Prize with
Martinus Veltman ʺfor elucidating the quantum
structure of electroweak interactions in physicsʺ.
Gerard ’t Hooft is also member of the Solvay Scientific
Committee for Physics.
Press release of the Nobel Foundation (1999):
Particle physics theory on firmer mathematical foundation
The everyday objects in our surroundings are all built up of atoms, which consist of electrons and
atomic nuclei. In the nuclei there are protons and neutrons, which in turn are made up of quarks.
To study matter at this innermost level, large accelerators are required. Such machines were first
designed in the 1950s, signifying the birth of modern particle physics. For the first time it was
possible to study the creation of new particles and the forces that act between them.
Around the middle of the 1950s, a first version of the modern theory was also formulated. Many
years of work have now resulted in the standard model of particle physics. This model groups all
elementary particles into three families of quarks and leptons, which interact with the help of a
number of exchange particles for the strong and the electro‐weak forces (Fig 1).
The theoretical foundation of the standard model was at first incomplete mathematically and in
particular it was unclear whether the theory could be used at all for detailed calculations of
physical quantities. Gerardus ʹt Hooft and Martinus J. G. Veltman are being awarded this
yearʹs Nobel Prize for having placed this theory on a firmer mathematical foundation. Their work
has given researchers a well functioning ʺtheoretical machineryʺ which can be used for, among
other things, predicting the properties of new particles.
More information at: http://nobelprize.org/physics/laureates/1999/thooft‐autobio.html
http://www.phys.uu.nl/%7Ethooft/

I. ‐c‐
Steven Weinberg
Steven Weinberg is Professor of Physics at the
University of Texas at Austin. In 1979, he was
awarded the Nobel Prize with Sheldon Glashow
and Abdus Salam ʺfor their contributions to the
theory of the unified weak and electromagnetic
interaction between elementary particles, including,
inter alia, the prediction of the weak neutral
currentʺ.
From the press release of the Nobel Foundation (1979):
The discovery of the radioactivity of certain heavy elements towards the end of last century, and
the ensuing development of the physics of the atomic nucleus, led to the introduction of two new
forces or interactions: the strong and the weak nuclear forces. Unlike gravitation and
electromagnetism these forces act only at very short distances, of the order of nuclear diameters or
less. While the strong interaction keeps protons and neutrons together in the nucleus, the weak
interaction causes the so‐called radioactive beta‐decay. The typical process is the decay of the
neutron: the neutron, with charge zero, is transformed into a positively charged proton, with the
emission of a negatively charged electron and a neutral, massless particle, the neutrino.
Although the weak interaction is much weaker than both the strong and the electromagnetic
interactions, it is of great importance in many connections. [...] The energy of the sun, allimportant
for life on earth, is produced when hydrogen fuses or burns into helium in a chain of
nuclear reactions occurring in the interior of the sun. The first reaction in this chain, the
transformation of hydrogen into heavy hydrogen (deuterium), is caused by the weak force.
Without this force solar energy production would not be possible. [...] The weak interaction finds
practical application in the radioactive elements used in medicine and technology, which are in
general beta‐radioactive, and in the beta‐decay of a carbon isotope into nitrogen, which is the basis
for the carbon‐14 method for dating of organic archaeological remains.
The theory which is awarded this yearʹs prize, and which was developed in separate works by the
prizewinners in the 60ʹs, has extended and deepened our understanding of the weak force by
displaying a close relationship to the electromagnetic force: these two forces emerge as different
aspects of a unified electroweak interaction. This means e.g. that the electron and the neutrino
belong to the same family of particles; the neutrino is the electronʹs little brother. [...]. The
importance of the new theory is first of all intrascientific. The theory has set a pattern for the
description also of the strong nuclear force and for efforts to integrate further the interactions
between elementary particles.
More information: http://nobelprize.org/physics/laureates/1979/weinberg‐autobio.html
http://www.ph.utexas.edu/~weintech/swbio.html

I. ‐c‐
Frank Wilczek
Frank Wilczek is Professor of Physics at the
Massachusetts Institute of Technology. In 2004, he
obtained the Nobel Prize with David Gross and
David Politzer ʺfor the discovery of asymptotic
freedom in the theory of the strong interactionʺ.
Press release from the Nobel Foundation (2004):
A ʹcolourfulʹ discovery in the world of quarks
What are the smallest building blocks in Nature? How do these particles build up everything we
see around us? What forces act in Nature and how do they actually function? This yearʹs Nobel
Prize in Physics deals with these fundamental questions, problems that occupied physicists
throughout the 20th century and still challenge both theoreticians and experimentalists working
at the major particle accelerators.
David Gross, David Politzer and Frank Wilczek have made an important theoretical
discovery concerning the strong force, or the ʹcolour forceʹ as it is also called. The strong force is
the one that is dominant in the atomic nucleus, acting between the quarks inside the proton and
the neutron. What this yearʹs Laureates discovered was something that, at first sight, seemed
completely contradictory. The interpretation of their mathematical result was that the closer the
quarks are to each other, the weaker is the ʹcolour chargeʹ. When the quarks are really close to each
other, the force is so weak that they behave almost as free particles. This phenomenon is called
”asymptotic freedom”. The converse is true when the quarks move apart: the force becomes
stronger when the distance increases. This property may be compared to a rubber band. The more
the band is stretched, the stronger the force.
This discovery was expressed in 1973 in an elegant mathematical framework that led to a
completely new theory, Quantum ChromoDynamics, QCD. This theory was an important
contribution to the Standard Model, the theory that describes all physics connected with the
electromagnetic force (which acts between charged particles), the weak force (which is important
for the sunʹs energy production) and the strong force (which acts between quarks). With the aid of
QCD physicists can at last explain why quarks only behave as free particles at extremely high
energies. In the proton and the neutron they always occur in triplets.
Thanks to their discovery, David Gross, David Politzer and Frank Wilczek have brought physics
one step closer to fulfilling a grand dream, to formulate a unified theory comprising gravity as
well – a theory for everything.
More information at http://nobelprize.org/physics/laureates/2004/wilczek‐autobio.html
http://web.mit.edu/physics/facultyandstaff/faculty/frank_wilczek.html

I. ‐c‐
Shing‐Tung Yau
Shing‐Tung Yau is Professor of
Mathematics at the University of Harvard.
In 1982, he was awarded the Fields Medal.
His work has many applications to gravity
and to string theory.
Short biography from
http://wwwgroups.dcs.stand.ac.uk/~history/Mathematicians/Yau.html
(Please follow the above link for the full text)
Shing‐Tung Yau studied for his doctorate at the University of California at Berkeley under
Chernʹs supervision. He received his Ph.D. in 1971. [...] In 1988 he was appointed professor at
Harvard University.
Yau was awarded a Fields Medal in 1982 for his contributions to partial differential equations, to
the Calabi conjecture in algebraic geometry, to the positive mass conjecture of general relativity
theory, and to real and complex Monge‐Ampère equations.
Nirenberg described Yauʹs work at the International Congress in Warsaw in 1983. Nirenberg
wrote:
“S‐T Yau has done extremely deep and powerful work in differential geometry and partial
differential equations. He is an analystʹs geometer (or geometerʹs analyst) with enormous
technical power and insight. He has cracked problems on which progess has been stopped for
years.”
Nirenberg describes briefly the areas of Yauʹs work. On the Calabi conjecture, which was made in
1954, he writes that this:
“... comes from algebraic geometry and involves proving the existence of a Kähler metric, on a
compact Kähler manifold, having a prescribed volume form. The analytic problem is that of
proving the existence of a solution of a highly nonlinear (complex Monge‐Ampère ) differential
equation. Yauʹs solution is classical in spirit, via a priori estimates. His derivation of the
estimates is a tour de force and the applications in algebraic geometry are beautiful.”
Yau solved the Calabi conjecture in 1976. Another conjecture solved by Yau was the positive mass
conjecture, which comes from Riemannian geometry. Yau, in joint work, constructed minimal
surfaces, studied their stability and made a deep analysis of how they behave in space‐time. His
work here has applications to the formation of black holes. [...]
Further information: http://www.fields.utoronto.ca/aboutus/jcfields/fields_medal.html

I. ‐c‐
From the International Solvay Institutes
The press conference will be directed by Marc Henneaux,
Professor of mathematical physics at the “Université Libre de
Bruxelles” and Director of the International Solvay Institutes.
The work of Henneaux focuses on gravity and related topics.
In 2000, Henneaux was awarded the Francqui Prize, the highest
scientific distinction in Belgium.
http://www.ulb.ac.be/sciences/ptm/pmif/membres/henneaux.html
Franklin Lambert is Professor of mathematical physics at the
“Vrije Universiteit Brussel” and Deputy‐Director of the
International Solvay Institutes.
His work focuses on integrable systems.
Alexandre Sevrin is Professor of theoretical physics at the “Vrije
Universiteit Brussel” and Secretary of the Scientific Committee
for Physics of the International Solvay Institutes.
His work deals with questions in theoretical high energy
physics and string theory.

I. –d‐
The 23 rd Solvay Conference on Physics
“The Quantum Structure of Space and Time”
Short presentation of the other invited participants

I. –d‐
We give below a short presentation of the other invited participants which is
inevitably incomplete and does not give the list all the distinctions and scientific
contributions of the participants. More information can usually be found on their
personal pages, the address of which is also given.
&&&&&&&
Nima Arkani‐Hamed is Professor of Theoretical Physics at Harvard University.
He got his Ph.D at the University of Berkeley in 1997. His research interests range
from the standard model of particle physics to cosmology and the challenging
mystery of the “dark energy”. He has also investigated the potential experimental
signatures of quantum gravity.
http://www.physics.harvard.edu/people/facpages/arkani‐hamed.html
Abhay Ashtekar is Eberly Professor of Physics at Penn State University, where he
is Director of the Institute for Gravitational Physics and Geometry. . His expertise
covers Einstein theory of gravity, where he has made many major contributions. In
particular, he has championed a novel approach to quantum gravity (“loop quantum
gravity”).
http://cgpg.gravity.psu.edu/people/Ashtekar/
Costas Bachas is “Directeur de recherche” at the CNRS and carries his work at the
“Ecole Normale Supérieure” (Paris). He is a leading expert in string theory, quantum
field theory and particle physics, to which he has significantly contributed. He has
been involved in many initiatives for popularizing current research to the general
public.
http://www.lpt.ens.fr/~bachas/
Tom Banks is Professor of Phyics at Rutgers University. He has made key
contributions to theoretical elementary particle physics, cosmology and string theory.
His recent work deals with the search for the yet‐to‐be‐found fundamental
formulation of string theory, where he has developed what is known as “Matrix
Theory”.
http://www.physics.rutgers.edu/people/hpgs/BanksT.html
Lars Brink is Professor of Physics at Chalmers University in Göteborg. He is a
member of the Royal Swedish Academy of Sciences and of the Nobel Committee.
His research interests focus on theoretical particle physics and string theory, where
he was a pioneer. He made central contributions to superstring theory and to
supersymmetric field theories.
http://nobelprize.org/physics/articles/brink/cv.html

I. –d‐
Claudio Bunster is co‐founder and Director of the “Centro de Estudios
Cientifícos” in Valdivia, Chile. He has been elected foreign associate of the American
Academy of Arts and Sciences. His expertise covers gauge theories and gravity,
where he contributed many crucial advances, in particular to the understanding of
black holes and black hole entropy.
http://www.cecs.cl/web/cecs_index.php?area=cecs&dep=fisica&idioma=en&pagina=i
nvestigador&id=19
Curtis Callan is Professor of Physics at Princeton University. His research areas
range from particle physics and string theory to the quantum theory of black holes
and condensed matter physics. In 2004, he has been named a winner of the Dirac
Medal “for his substantial contributions to particle physics including, more recently,
to string theory”.
http://pupgg.princeton.edu/www/jh/research/Callan_Curtis.htmlx
Thibault Damour is Professor of Physics at the “Instituts des Hautes Etudes
Scientifiques” (France). He is a member of the French Academy of Sciences. He is a
world figure in Einstein theory of gravity. He was awarded the Einstein Medal in
1996 for recognition of his seminal work in this area. He has recently written popular
books on the subject.
http://www.ihes.fr/~damour/
Jan de Boer is Professor at the Institute for Theoretical Physics at the University of
Amsterdam. His expertise covers theoretical high‐energy physics as well as gravity.
He has made significant advances to understanding the various “duality”
connections between quantum field theory on the one hand and string theory on the
other hand.
http://remote.science.uva.nl/~jdeboer/
Bernard de Wit is Professor at the Institute for Theoretical Physics at the
University of Utrecht. His research interests deal with quantum gravity, strings and
elementary particles. He is an expert in supergravity theories – supersymmetric
extensions of gravity which control the low energy limits of string theory ‐ where he
made pioneering contributions.
http://www.phys.uu.nl/~bdewit/
Robbert Dijkgraaf is University Professor at the University of Amsterdam and
member of the Royal Netherlands Academy of Arts and Sciences (KNAW). His
research covers string theory, quantum gravity, and the interface of mathematics and
particle physics. In 2003, he was awarded the NWO Spinoza prize, the highest
distinction in the Netherlands.
http://staff.science.uva.nl/~rhd/

I. –d‐
Public event: Professor Dijkgraaf has always been interested in creating more public
awareness of mathematics and science and will deliver one of the public lectures on
December 4.
Michael Douglas is Professor of Physics at Rutgers University. His research is in
string theory as a theory of fundamental interactions and quantum gravity, and in
non‐perturbative methods in field theory. He made numerous significant
contributions to various aspects of string theory at the frontiers of mathematics.
http://www.physics.rutgers.edu/people/pdps/Douglas.html
Georgi Dvali is Professor of Physics at New York University. His research is at the
intersection between particle physics and cosmology. In particular, he is a worldexpert
in the cosmological and other implications of string theory, such as e.g., the
origin of inflation, the nature of the extra dimensions and the origin of low energy
hierarchies.
http://www.physics.nyu.edu/people/dvali.georgi.html
Ludwig Faddeev is Director of the Euler Mathematical Institute (Steklov Institute)
in St. Petersburg and a member of the Russian Academy of Sciences. He is a leading
figure in quantum field theory and mathematical physics. In 1990, he received the
Dirac Medal for his “decisive contributions to the quantization of the Yang‐Mills and
gravitational fields”.
http://www.pdmi.ras.ru/staff/faddeev.html
Solvay Committee: Professor Faddeev is a member of the Solvay Scientific
Committee for physics.
Pierre Fayet is Professor at the “Ecole Polytechnique” (Paris) and “Directeur de
recherches” at the CNRS. He carries his work at the “Ecole Normale Supérieure”.
He is a member of the French Academy of Sciences. His expertise covers cosmology
and particle physics, where he made pioneering work in the building of
supersymmetric extensions of the standard model.
http://www.lpt.ens.fr/
Willy Fischler is Professor of Physics at the University of Texas at Austin. He got
his Ph.D at the “Université Libre de Bruxelles” under the supervision of Robert
Brout. He is a world leader in field theory, supersymmetry, string theory, quantum
cosmology and statistical mechanics. His most recent work focuses on cosmology
and the origin of inflation.
http://www.ph.utexas.edu/~weintech/fischler.html

I. –d‐
Peter Galison is Mallinckrodt Professor of the History of Science and of Physics at
Harvard University. He is a leading figure in the history of sciences. His work
explores in particular twentieth century microphysics (atomic, nuclear, particle
physics). He is the author of several books, among which Einsteinʹs Clocks and
Poincaréʹs Maps: Empires of Time (2003).
http://physics.harvard.edu/people/facpages/galison.html
Gary Gibbons is Professor of Theoretical Physics in DAMTP at the University of
Cambridge, where he holds a professorship position at Trinity College. He was
elected Fellow of the Royal Society in 1999. He is an expert in relativity and
gravitation. He is known worldwide for his deep contributions to quantum gravity
and black hole physics.
http://www.damtp.cam.ac.uk/user/gr/about/members/gibbons.html
Michael Green is Professor of Theoretical Physics at the University of Cambridge.
He is a leading figure in string theory. In 1989, he was awarded the Dirac medal
“for his basic contributions” to it and in 2002, he received the Danie Heineman Prize
of the American Physical Society ʺfor his pioneering work in the development of
superstring theory.ʺ http://www.damtp.cam.ac.uk/user/mbg15/
Brian Greene is Professor of Physics and Mathematics at Columbia University,
where he is co‐director of the Institute for strings, cosmology and astroparticle
physics. He is one of the world’s foremost string theorists. He is in particular one of
the fathers of mirror symmetry, a crucial concept in the field. His most recent work
deals with cosmology.
http://columbia‐physics.net/faculty/greene_main.htm
Public event: Professor Greene is the author of the bestselling book “The Elegant
Universe”, a popularization of string theory. His second book, “The Fabric of the
Cosmos” is about space, time and the nature of the universe. He will deliver one of
the public lectures on December 4.
Alan Guth is Victor F. Weisskopf Professor of Physics at the Massachusetts Institute
of Technology. His fields of expertise are elementary particle physics and
cosmology. He is one of the fathers of the inflationary universe cosmological model.
In 2002, he was awarded the Dirac medal “for the development of the concept of
inflation in cosmology”.
http://web.mit.edu/physics/facultyandstaff/faculty/alan_guth.html

I. –d‐
James Hartle is Professor of Physics at the University of California at Santa
Barbara. He has made fundamental contributions to quantum gravity and to the
problem of the initial conditions of the universe. His research efforts also explore the
generalizations of quantum mechanics needed to accommodate quantum spacetime
geometry.
http://gabriel.physics.ucsb.edu/~hartle/
Jeffrey Harvey is Professor of Physics at the University of Chicago and a member
of the Enrico Fermi Institute. His research focuses on string theory and particle
physics. He is one of the fathers of the heterotic string model, whose discovery was a
major breakthrough in the area. More recently, he has been interested in non
commutative field theory.
http://hamilton.uchicago.edu/~harvey/
Gary Horowitz is Professor of Physics at the University of California at Santa
Barbara. His research is mostly focused on questions involving gravity under the
most extreme conditions (“singularities”), which include the big bang in cosmology
and the spacetime inside black holes, questions to which he made essential
contributions.
http://gabriel.physics.ucsb.edu/~gary/
Bernard Julia is “Directeur de recherche” at the CNRS and carries his work at the
“Ecole Normale Supérieure” (Paris). His interests range from string theory to chaos,
and, more generally, to all topics at the frontiers of mathematics and theoretical
physics. He is known worldwide as one of the discoverers of 11‐dimensional
supergravity.
http://www.lpt.ens.fr/~julia/
Shamit Kachru is Associate Professor at Stanford University. He obtained his
Ph.D at Princeton University in 1994. He is interested in the physics of string theory.
His work has focused on the fascinating questions of stringy modifications of
geometry, duality and exact results in supersymmetric compactifications of extra
dimensions.
http://www.stanford.edu/dept/physics/people/faculty/kachru_shamit.html
Renata Kallosh is Professor of Physics at Stanford University. Her research
involves gravity, supersymmetry, supergravity and string theory, where she made
important contributions. Most recently she has explored the cosmology of the very
early universe and has analysed how to reconcile the observed dark energy with
string theory (cosmological constant).
http://www.stanford.edu/dept/physics/people/faculty/kallosh_renata.html

I. –d‐
Elias Kiritsis is member of the centre for theoretical physics at the “Ecole
Polytechnique” (Paris) and Professor of Theoretical Physics at the University of
Crete. He made many central contributions to string theory and quantum field
theory in general, in particular to non‐perturbative aspects of supersymmetric
theories and conformal field theory.
http://cpht.polytechnique.fr/cpth/kiritsis/
Igor Klebanov is Professor of Physics at Princeton University. His interests range
from particle physics, gauge field theory, black holes and string theory. He
pioneered essential aspects of the interplay between string theory and (conformal)
quantum gauge field theory. He has also maintained an interest in nuclear physics
(in particular the so‐called pentaquark).
http://pupgg.princeton.edu/www/jh/research/Klebanov_Igor.htmlx
Andrei Linde is Professor of Physics at Stanford University. He is one of the fathers
of inflationary cosmology and of the theory of the cosmological phase transitions,
which remain the main subject of his work. He received many distinctions, including
the Dirac medal in 2002 “for the development of the concept of inflation in
cosmology”.
http://www.stanford.edu/~alinde/
Dieter Lüst is Professor at the University of Munich and Director at the “Max‐
Planck‐Institut für Physik (Werner‐Heisenberg‐Institut)” in that same city. His expertise
covers particle physics and string theory. He is known worldwide for his study of
low‐energy aspects of four‐dimensional strings, aimed at making contact with
phenomenology and observations.
http://wwwth.mppmu.mpg.de/members/luest/
Juan Maldacena is Professor at the School of Natural Sciences of the Institute for
Advanced Study in Princeton. He is a world leader in string theory and gravitation
physics. He made seminal work to the understanding of black hole entropy in the
context of string theory and more recently, to the duality between gauge theories and
gravity.
http://www.sns.ias.edu/~malda/
Nikita Nekrasov is Professor of Physics at the “Instituts des Hautes Etudes
Scientifiques” (France). He obtained his Ph.D in 1996 at Princeton University under
the supervision of David Gross. He works in non‐perturbative aspects of quantum
field theory and string theory. He made essential contributions to noncommutative
field theory.
http://www.ihes.fr/~nikita/index.html

I. –d‐
Hermann Nicolai is Director at the Max‐Planck‐Institut für Gravitationphysik
(Albert Einstein Institute). His work is concerned with various aspects of quantum
gravity and unified theories, especially supergravity, superstring and
supermembrane theories. He made pioneering contributions to supergravity theories
and to the understanding of their structure.
http://www.aei.mpg.de/english/contemporaryIssues/members/db_members/index.p
hp
Hirosi Ooguri is Professor of Theoretical Physics at the Californian Institute of
Technology. His research interests are in theoretical high energy physics, in
particular in quantum field theories and string theory. He has made central
contributions to the understanding of crucial mathematical properties of strings. He
is also the author of various popular science articles.
http://www.theory.caltech.edu/~ooguri/
Joseph Polchinski is Professor of Physics at the University of California at Santa
Barbara and permanent member of the Kavli Institute for Theoretical Physics. He is a
member of the American Academy of Arts and Sciences. He is one of the leading
field and string theorists of his generation. His discovery of “D‐branes” revolutioned
string theory.
http://theory.itp.ucsb.edu/~joep/
Alexander Polyakov is Professor of Physics at Princeton University. His interests
cover almost all areas of theoretical physics. He was awarded the Dirac medal in
1986 for “being among the first to emphasize the importance of scale invariance in
quantum field theory, particularly in connection with critical phenomena”, and the
Lorentz medal in 1994.
http://pupgg.princeton.edu/www/jh/research/Polyakov_Alexander.htmlx
Eliezer Rabinovici is Professor at the Hebrew University in Jerusalem and
member of its Racah Institute of Physics. His expertise covers particle theory, field
theory and string theory. He has made numerous important contributions to the
subject of string duality and to global aspects of string compactifications to lower
dimensions.
http://www.phys.huji.ac.il/~eliezer/

I. –d‐
Pierre Ramond is Distinguished Professor at the University of Florida at
Gainesville and Director of the Institute for Fundamental Theory. His interests range
from particle phenomenology to string theory. He is one of the fathers of string
theory and discovered the first string model that contained fermions. He is also a
world leader in neutrino physics.
http://www.phys.ufl.edu/~ramond/
Solvay Committee: Professor Ramond is a member of the Solvay Scientific
Committee for physics.
Lisa Randall is Professor of Physics at Harvard University. She is a member of the
American Academy of Arts and Sciences. Her research concerns the fundamental
nature of particles and forces. She has made seminal contributions to many areas
including cosmological inflation, baryogenesis and theories of extra dimensions of
space.
http://www.physics.harvard.edu/people/facpages/randall.html
Valery Rubakov works at INR (Moscow) and is a member of the Russian
Academy of Sciences. He is one of the prominent Russian theorists. His interests
cover quantum field theory and cosmology. In 2003, the Pomeranchuk Prize was
awarded to him for “pioneering contribution to developing and novel application of
nonperturbative methods in field theory”.
http://www.inr.ac.ru/
John Schwarz is Professor at the Californian Institute of Technology. He is a
member of the American Academy of Arts and Sciences. He is one of the fathers of
string theory and played a pioneering role in supersymmetric field theories. In 1989,
he was awarded the Dirac medal “for his basic contributions to the development of
superstring theory”.
http://www.theory.caltech.edu/people/jhs/
Nathan Seiberg is Professor at the School of Natural Sciences of the Institute for
Advanced Study in Princeton and a fellow of the American Academy of Arts and
Sciences. His work focuses on various aspects of string theory and field theory. He
made seminal contributions to supersymmetric gauge theories for which he received
in 1998 the Dannie Heineman Prize.
http://www.sns.ias.edu/~seiberg/

I. –d‐
Ashoke Sen works at the Harish‐Chandra Research Institute in Allahabad (India).
He was elected fellow of the National Academy of Sciences of India in 1997 and
fellow of the Royal Society (London) in 1998. His interests focus on field theory,
gravity and superstrings. He made essential contributions to the understanding of
duality and to string field theory.
http://www.mri.ernet.in/~sen/
Stephen Shenker is Professor at Stanford University and Director of the Stanford
Institute for Theoretical Physics. His research interests focus on field theory and
string theory, to which he contributed significant advances, in particular, to its
nonperturbative aspects, including matrix formulations. More recently, he has
worked on cosmology.
http://www.stanford.edu/dept/physics/people/faculty/shenker_stephen.html
Eva Silverstein is Associate Professor at Stanford University. She obtained her
Ph.D degree in 1996 from Princeton University. Her interests cover particle physics,
gravity and string theory. She is known worldwide for her central contributions to
these areas, in particular to the microphysics of dark energy in string theory as well
as to the problem of singularities.
http://www.slac.stanford.edu/slac/faculty/hepfaculty/silverstein.html
Paul Steinhardt is the Albert Einstein Professor in Science at Princeton University
and a member of the American Academy of Arts and Sciences. His research spans
problems in particle physics, astrophysics, cosmology and condensed matter physics.
He is one of the architects of the ``inflationary modelʺ, for which he received the
Dirac medal in 2002.
http://wwwphy.princeton.edu/~steinh/
Andrew Strominger is Professor of Physics at Harvard University. His research
concerns quantum gravity, string theory and quantum field theory. His most famous
work deals with black hole entropy, where he was able to give a microscopic
derivation from string theory of the Bekenstein‐Hawking entropy originally derived
through thermodynamical arguments.
http://physics.harvard.edu/people/facpages/strominger.html
Neil Turok is Professor of Mathematical Physics at the University of Cambridge
and one of the Directors of the African Institute for Mathematical Sciences in Cape
Town. He made many key contributions to theoretical physics. He has a long
standing interest in cosmology. He proposed recently an alternative to inflation,
where string ideas play a central role.
http://www.damtp.cam.ac.uk/user/ngt1000/

I. –d‐
Gabriele Veneziano is Professor at the “Collège de France” and senior staff
member at CERN. He is also member of various Academies of Sciences. Co‐inventor
of string theory, he is now focusing his research on cosmology and the “pre‐big‐bang
model”. He received the Pomeranchuk Prize, and in 2004, the Dannie Heinemann
for his “pioneering discoveries”.
http://www.college‐de‐france.fr/site/par_ele/
Paul Windey is Professor of Physics at the University of Paris VI. He got his Ph.D
at the “Université Libre de Bruxelles” under the supervision of François Englert. His
domains of expertise cover quantum gravity, string theory and quantum field theory,
where he made many important contributions concerning e.g. magnetic monopoles
or black holes.
http://string.lpthe.jussieu.fr/lpthe/members.pl?key=45

I. –d‐
PICTURE GALLERY
Nima Arkani‐Hamed
Abhay Ashtekar
Costas Bachas
Tom Banks
Lars Brink
Claudio Bunster
(Teitelboim)
Curtis Callan
Thibault Damour
Jan de Boer

I. –d‐
Bernard de Wit
Robbert Dijkgraaf
Michael Douglas
Georgi Dvali
Ludwig Faddeev
Pierre Fayet
Willy Fischler
Peter Galison
Gary Gibbons
Michael Green
Brian Greene
Alan Guth

I. –d‐
James Hartle
Jeffrey Harvey
Gary Horowitz
Bernard Julia
Shamit Kachru
Renata Kallosh
Elias Kiritsis
Igor Klebanov
Andrei Linde
Dieter Lüst
Juan Maldacena
Nikita Nekrasov

I. –d‐
Hermann Nicolai
Hirosi Ooguri
Joseph Polchinski
Alexander Polyakov
Eliezer Rabinovici
Pierre Ramond
Lisa Randall
Valery Rubakov
John Schwarz
Nathan Seiberg
Ashoke Sen
Stephen Shenker

I. –d‐
Eva Silverstein
Paul Steinhardt
Andrew Strominger
Neil Turok
Gabriele Veneziano
Paul Windey

I. ‐e‐
23 rd Solvay Conference in Physics
“The Quantum Structure of Space and Time”
Scientific Programme
Morning (9 am – 12 am) :
Afternoon (2 pm – 5 pm) :
Morning (9 am – 12 am) :
Morning (9 am – 12 am) :
Afternoon (2 pm – 5 pm) :
Afternoon (5 pm – 5:30 pm) :
Thursday, December 1 st , 2005
“Opening & History”
Chair : M. HENNEAUX
Rapporteur : P. GALISON
“Quantum Mechanics”
Chair : D. GROSS (gross@kitp.ucsb.edu)
Rapporteur : J. HARTLE
“Singularities”
Chair : G. HOROWITZ (gary@physics.ucsb.edu)
Rapporteur : G. GIBBONS
Friday, December 2 nd , 2005
“Mathematical Structures”
Chair : H.OOGURI (ooguri@theory.caltech.edu)
Rapporteur : R. DIJKGRAAF
Saturday, December 3 rd , 2005
“Emergent Spacetime”
Chair : J. HARVEY (harvey@theory.uchicago.edu)
Rapporteur : N. SEIBERG
“Cosmology”
Chair : S. SHENKER (sshenker@stanford.edu)
Rapporteur : J. POLCHINSKI
“Concluding Remarks”
D. GROSS

II. ‐a‐
The Solvay Conference public event
Sunday 4 December 2005 at 14:00
General information
What is the origin of the Universe? Is the Universe finite? Could we fall into a black hole? Will time
travel ever be possible? During the public event you will have the possibility to meet Nobel Prize
laureates and other famous scientists, and ask them your questions about the Universe!
The event
For the very first time in its history the prestigious Solvay Conference opens its doors to the
public! Indeed, a half‐day public event will follow the 23 rd Solvay Conference in Physics
which will take place in Brussels from December 1 to 3.
During this afternoon, people you will have the possibility to follow the talks given by the
famous scientists Robbert Dijkgraaf 1 and Brian Greene 2 on major topics in physics, to meet
the Nobel Prize laureates David Gross 3 (2004) and Gerard ’t Hooft 4 (1999) as well as other
participants in the 2005 Solvay Conference, and to ask them your questions about the
Universe.
People can ask their questions about the Universe on the website in advance.
A contest “journalist for one day” is also organised for secondary school students.
The public event will take place in the “Charlemagne” building of the European Commission
(Rue de la Loi, 170 ‐ 1040 Brussels). Registration, questions, practical information and
programme: www.europa.eu.int/solvay2005
1 http://staff.science.uva.nl/~rhd/
2 http://www.pbs.org/wgbh/nova/elegant/greene.html
3 http://www.physics.ucsb.edu/
4 http://www.phys.uu.nl/~thooft/

II. ‐b‐
The Solvay Conference public event
Programme of the event
12:30 – 14:00 Access to the building
Registration of the participants
Welcome Coffee
14:00 – 14:15 Opening address by Philippe Busquin (Member of
the European Parliament)
Introduction of the speakers by Marc Henneaux
(Solvay Institutes and ULB)
14:15 – 14:55 Talk by Robbert Dijkgraaf “Strings, Black Holes and
the End of Space and Time”
14:55 – 15:35 Talk by Brian Greene “The Fabric of the Cosmos: Space,
Time and the Texture of Reality”
15:35 – 16:35 Debate chaired by David Gross (Santa Barbara,
Nobel Laureate in Physics 2004) with the
participation of Thibault Damour (IHES), Robbert
Dijkgraaf (Amsterdam), Brian Greene (Columbia),
Gerard ’t Hooft (Utrecht, Nobel Laureate in Physics
1999), Lisa Randall (Harvard) et Gabriele Veneziano
(Collège de France),
led by Michel Claessens (European Commission)
16:35 – 16:40 Closing address by Jean‐Michel Baer (European
Commission)
16:40 – 18:00 Cocktail

III.
The Solvay Conferences on Physics
A brief history
The 23d Solvay Conference on Physics, to be held between 1 and 3 December,
continues a tradition of high‐level meetings, dating back almost a century, which
tackle high‐order scientific issues. Top scientists have always been drawn to Solvay
events. Indeed, the very first conference – the 1911 ‘Conseil Solvay’ on radiation and
the quanta’ – assembled the famous physicists and chemists of the day, including
Marie Curie, Albert Einstein, Max Planck, Ernest Rutherford, Henri Poincaré and
Maurice de Broglie.
In the wake of this event, the International Solvay Institute for Physics was founded,
by Ernest Solvay in 1912, and its sister institute in chemistry appeared the year after.
The Physics Institute’s mission was, and still is, to “promote research, the purpose of
which is to enlarge and deepen the understanding of natural phenomena […]
without excluding problems belonging to other areas of science provided that these
are connected with physics”. The Conference on Physics – and other activities under
the Institutes’ auspices – underscores this primary vision.
The remarkable success of the Solvay Conferences owes much to the exceptional
stature of the leading scientists who chaired them, among which H.A. Lorentz (1902
Nobel Laureate in Physics), P. Langevin, L. Bragg (1915 Nobel Laureate in Physics),
R. Oppenheimer and today D. Gross (2004 Nobel Laureate in Physics).
Besides the celebrated Conferences of 1911 and 1927, whose pictures are renowned
worldwide, many other Conferences are to be noted. For instance, the 1958
Conference has witnessed the famous debate between R. Oppenheimer and J.A.
Wheeler on what was to become known as “black holes” (a debate vividly described
in the recent popular book by K.S. Thorne “Black Holes and Time Warps: Einstein’s
Outrageous Legacy”). More recently, the last Solvay Conference on physics held in
Brussels (1991) focused on quantum optics, a discipline that has just been rewarded
again by the Nobel Academy.
Except for the 18th, 19th, 21st and 22nd Conferences, all Solvay Conferences in
Physics took place in Brussels.

III.
List of Solvay Conferences on Physics
1. 1 st Conference – 1911 – « La théorie du rayonnement et les quanta » ‐ chaired by
H.A. Lorentz
2. 2 nd Conference – 1913 – « La structure de la matière » ‐ chaired by H.A. Lorentz
3. 3 rd Conference – 1921 – « Atomes et électrons » ‐ chaired by H.A. Lorentz
4. 4 th Conference – 1924 – « Conductibilité électrique des métaux et problèmes
connexes » ‐ chaired by H.A. Lorentz
5. 5 th Conference – 1927 – « Electrons et photons » ‐ chaired by H.A. Lorentz
6. 6 th Conference – 1930 – « Le magnétisme » ‐ chaired by P. Langevin
7. 7 th Conference – 1933 – « Noyaux atomiques » ‐ chaired by P. Langevin
8. 8 th Conference – 1948 – « Les particules élémentaires » ‐ chaired by L. Bragg
9. 9 th Conference – 1951 – « L’état solide » ‐ chaired by L. Bragg
10. 10 th Conference – 1954 – « Les électrons dans les métaux » ‐ chaired by L. Bragg
11. 11 th Conference – 1958 – « La structure et l’évolution de l’univers » ‐ chaired by
L. Bragg
12. 12 th Conference – 1961 – « La théorie quantique des champs » ‐ chaired by L.
Bragg
13. 13 th Conference – 1964 – « The Structure and Evolution of Galaxies » ‐ chaired by
R. Oppenheimer
14. 14 th Conference – 1967 – « Fundamental Problems in Elementary Particle
Physics » ‐ chaired by C. Møller
15. 15 th Conference – 1970 – « Symmetry Properties of Nuclei » ‐ chaired by E.
Amaldi
16. 16 th Conference – 1973 – « Astrophysics and gravitation » ‐ chaired by E. Amaldi
17. 17 th Conference – 1978 – « Order and Fluctuations in Equilibrium and
Nonequilibrium Statistical Mechanics » ‐ chaired by L. Van Hove
18. 18 th Conference – 1982 – « Higher energy physics. What are the possibilities for
extending our understanding of elementary particles and their interactions to much
greater energies? » ‐ chaired by L. Van Hove
19. 19 th Conference – 1987 – « Surface Sciences » ‐ chaired by F.W. de Wette
20. 20 th Conference – 1991 – « Quantum Optics » ‐ chaired by P. Mandel
21. 21 st Conference – 1998 – « Dynamical Systems and Irreversibility » ‐ organized
by I. Antoniou
22. 22 nd Conference – 2001 – « The Physics of Communication » ‐ organized by I.
Antoniou
23. 23 rd Conference – 2005 – « The Quantum Structure of Space and Time » ‐ chaired
by D. Gross

IV. ‐a‐
The Solvay Institutes
Short presentation
The mission of the International Institutes for Physics and Chemistry, founded by E.
Solvay, is to develop and promote high level fundamental research in physics,
chemistry and related areas (in particular, mathematics). The Solvay Institutes are
renowned worldwide thanks to the “Conseils de Physique Solvay”, a unique series of
conferences that have shaped modern physics.
Besides the organization of the prestigious Solvay Conferences, the Institutes carry
their own research. Ilya Prigogine, 1977 Nobel Laureate in chemistry, was Director
of the Institutes until his death in 2003.
At the core of the current research directions lies gravity (quantum gravity, string
theory, cosmology and related mathematical aspects), which is the subject of the 23 rd
Solvay conference. The other research lines are integrability and chaos, matter out of
equilibrium, and chemical reactivity.
The International Solvay Institutes support these research efforts through an active
program of top level workshops, invitations, fellowships and international chairs.
Among the recent or future activities, let us mention the symposium in the honor of
Henri Poincaré which was held in Brussels in 2004 on the occasion of the 150th
anniversary of his birth, or the symposium on chemical reactivity which will take
place in the Spring of 2006.
[For more information, see http://www.ulb.ac.be/sciences/ptm/pmif/intro.html].
Among the members of the Solvay Scientific Committees for Physics and for
Chemistry, one counts many Nobel Laureates.
Structure :
The International Solvay Institutes are a non‐profit organization with close ties to the
« Université Libre de Bruxelles » and the « Vrije Universiteit Brussel ». According to
their governing rules, the Administrative Board is composed as follows: 3
representatives from the ULB, 3 representatives from the VUB and 3 members
designated by the Solvay Family.
Administrative Board :
President : Mr. Solvay
Vice‐President : Mr. Franz Bingen (VUB)
Other Members : Mrs. Irina Veretennicoff (VUB), Baron Daniel Janssen, Mr.
Franklin Lambert (VUB), Mr. René Lefever (ULB), Mr. Grégoire Nicolis (ULB),
Mr. Jean‐Marie Piret, Mr. Jean‐Louis Van Herweghem (ULB)
Director : Mr. Marc Henneaux (ULB)
Deputy‐Director : Mr. Franklin Lambert (VUB)

IV. ‐b‐
The Solvay Institutes
Scientific Committee for Physics
Chair : Professor Herbert WALTHER, Max‐Planck‐Institut,
Munich, Germany.
Members (second term) :
(2004‐2009)
Professor Fortunato Tito ARECCHI, Università di Firenze
and INOA, Italy;
Professor Claude COHEN‐TANNOUDJI, Nobel Prize
1997, Ecole Normale Supérieure, Paris, France;
Professor Ludwig FADDEEV, V.A Steklov Mathematical
Institute,Saint‐Petersburg, Russia;
Professor Gerard ‘T HOOFT, Nobel Prize 1999, Spinoza
Instituut, Utrecht, The Netherlands.
Members (first term) :
(2004‐2009)
Professor Jocelyn BELL BURNELL, University of Bath,
UK;
Professor David GROSS, Nobel Prize 2004, Kavli Institute,
Santa Barbara, USA;
Professor Klaus VON KLITZING, Nobel Prize 1985, Max‐
Planck‐Institut, Stuttgart, Germany;
Professor Pierre RAMOND, University of Florida,
Gainesville, USA.
Scientific Secretary :
Professor Alexandre SEVRIN, Vrije Universiteit Brussel.

IV. ‐c‐
The International Institutes for Physics and Chemistry,
founded by Ernest Solvay,
acknowledge with gratitude the generous support of :
• the Solvay family,
• Solvay S.A.‐ N.V.,
• the Université Libre de Bruxelles,
• the Vrije Universiteit Brussel,
• the Belgian National Lottery,
• the Communauté Française de Belgique,
• the Foundation David and Alice Van Buuren,
• the Hôtel Métropole.
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