List of colloquia organized by Pierre van Baal
September 1993 - August 2000

The colloquium was initiated by Paul Ehrenfest in 1912. It is now called the Colloquium Ehrenfestii and traditionally takes place Wednesday evenings at 19:30 hours. After 1 hour there is a 15 minutes coffee/tea break and the speaker continues for another 15-30 minutes. It has been a good custom to interrupt the speaker with questions during the colloquium, frequently leading to interesting discussions.

From November 1998 a three course meal (including coffee and wine) is catered on site at 18:00 hours, for anyone attending the colloquium. The cost is kept low. The colloquium is generously sponsered already for many years by the Lorentz-Fonds, in memory of the other great theoretical physicist of Leiden, whose name is now attachted to the Instituut-Lorentz for theoretical physics, the guardian of the colloquium Ehrenfestii; it is still going strong today.

Programmes: 2000 1999 1998 1997 1996 1995 1994 1993 history

Colloquium Ehrenfestii in 2000

24 May

C.M. Varma (Bell Labs, Murray Hill/Leiden)

Quantum Criticality in the High Tc Superconductivity Phenomena

3 May

H. Satz (Bielefeld)

Quark Matter and Nuclear Collisions

12 Apr

D.I. Olive (Swansea/Utrecht)

Electromagnetic Duality

29 Mar

E.P.J. van den Heuvel (UvA)

Jan van Paradijs -- Legacy in Gamma-Ray Burst Research

8 Mar

D. Dieks (Utrecht)

Does space exist? A relationist view of space and time

16 Feb

H. van Driel (Toronto)

Quantum Interference Control of Semiconductors

26 Jan

B. Nienhuis (UvA)

Quasicrystals - what shall we do with the drunken tiler

Colloquium Ehrenfestii in 1999

8 Dec

R.H. Stuewer (Minneapolis)

The Case of the Elusive Particles: Nuclear Disintegration and the Cambridge-Vienna Controversy

24 Nov

A. Connes (IHES, Bures-sur-Yvette)

Noncommutative Geometry

10 Nov

H. Bohr (Lyngby, Denmark)

Coherent topological modes in Biomolecules

27 Oct

P. Grassberger (Jülich/Wuppertal)

Go with the winners: a simulation strategy between evolutionary and Monte Carlo algorithms

13 Oct

M.V. Berry (Bristol/Leiden)

Quantum Indistinguishability

22 Sep

A.D. Stone (Yale)

Classical and quantum chaos in asymmetric optical resonant cavities

15 Sep

R. Bruinsma (UCLA)

Physical aspects of DNA condensation

12 May

M. de Jong (NIKHEF)

Neutrino: masses, mixing and oscillations

21 Apr

A.K. Geim (Nijmegen)

When frogs fly and ideal diamagnets flaunt paramagnetism

14 Apr

S. Hunklinger (Heidelberg)

Indications for a macroscopic state of tunneling systems in glasses

24 Mar

J. de Boer (Leiden)

How much information does string theory give us?

3 Mar

D. Lohse (TU-Twente)

Sonoluminescence: When bubbles glow

10 Feb

C.H. Townes (Berkeley)

How the Laser Happened

20 Jan

K. Schoutens (UvA)

Fractional charge and statistics in quantum Hall systems

Colloquium Ehrenfestii in 1998

9 Dec

J.L. van Hemmen (TU München)

Sound Localization in the Barn Owl: Tuning Neuronal Hardware with Microsecond Precision

25 Nov

P.C.E. Stamp (UBC, Vancouver)

Quantum Irreversibility: The fundamental Mechanisms of Decoherence

4 Nov

W. Ketterle (MIT)

Keeping the focus on Bose-Einstein condensates

27 May

G. Veneziano (CERN, Geneva)

String Cosmology and the Beginning-of-Time Myth

13 May

S. Sachdev (Yale)

Dynamics near quantum phase transitions: a perspective on correlated electron systems

6 May

E. Otten (Mainz)

Measurement of the form factors of the neutron and the human lung with polarized He-3

22 Apr

F. Wilczek (IAS, Princeton/Leiden)

Getting Its from Bits: Modern Pythagorism

8 Apr

S. Leibler (Princeton/EMBL, Heidelberg)

On collective phenomena in the cell

1 Apr

V. Icke (Leiden/Amsterdam)

Death Becomes Them (the end of Sun-like stars)

18 Mar

B. Barbara (Neel lab., Grenoble)

Quantum and classical aspects of magnetisation reversal in nano-particles

4 Mar

J.P. Toennies (Goettingen)

How many 4He atoms are needed to make a superfluid?

11 Feb

H. Stoof (Utrecht)

The physics of Bose-Einstein condensates

28 Jan

G. Ahlers (UCSB/Bayreuth)

Experiments on spatio-temporal complexity

14 Jan

E. Verlinde (Utrecht)

From quantum fields to gravity and strings

Colloquium Ehrenfestii in 1997

10 Dec

J.G. van Ingen Schenau (VU, Amsterdam)

The physics of klapskating

26 Nov

A. Goldbeter (ULB, Brussel)

Theoretical study of oscillations and waves in intercellular communication

12 Nov

E. Salje (Cambridge)

Tweed and stripes - how solids relax

22 Oct

Th. Giamarchi (Orsay)

Bragg and Moving glasses: a theory for disordered vortex lattices

8 Oct

Ph. Grangier (Inst.d'Optique, Orsay)

Quantum non-demolition measurement

24 Sep

L.R.M. Maas (NIOZ, Texel)

Surprising behaviour of waves in stratified fluids

25 Jun

R.A. Mathies (Berkeley)

A coherent picture of visual photochemistry

4 Jun

B.L. Altshuler (Princeton)

Spectroscopy of quantum dots: exact quantum states and Landau quasiparticles

28 May

C.M. Marcus (Stanford)

Quantum chaos in quantum dots

7 May

T.W.B. Kibble (Imperial College, London)

Testing cosmological defect formation in the laboratory

23 Apr

B.I. Halperin (Harvard/Leiden)

The quantum Hall effects: quantized and unquantized

16 Apr

D. Bensimon (ENS, Paris)

Manipulation and elastic properties of DNA

2 Apr

R.C. Richardson (Cornell)

The remarkable properties of superfluid 3He

5 Mar

J.C. Maan (Nijmegen)

Composite fermions; a new way of looking at the "old" fractional quantum Hall effect

12 Feb

J. Fröhlich (ETH, Zürich)

Special Features of Condensed Matter Physics in one and two dimensions

5 Feb

D.P. DiVincenzo (IBM, Yorktown Heights)

Quantum computation

Colloquium Ehrenfestii in 1996

4 Dec

B.F. Schutz (MPI-Potsdam)

Gravitational waves from black holes

20 Nov

S. Kivelson (UCLA)

Pairing without condensation in high temperature superconductors

6 Nov

A. Zeilinger (Innsbruck)

Experiment, entanglement and the foundations of quantum physics

30 Oct

M. Devoret (Saclay)

Do resistors make shot noise?

23 Oct

Y. Imry (Weizmann/Leiden)

Electron interaction effects in quantum dots

25 Sep

N.J. van Druten (Leiden)

Bose-Einstein condensation: Atomic identity crisis

4 Sep

T. Bohr (NBI, Copenhagen)

Another kind of turbulence

1 May

R. Packard (Berkeley)

The role of the a.c. Josephson equation in superfluid Helium

17 Apr

T. Jacobson (Maryland/Utrecht)

Black holes and the transplanckian puzzle

20 Mar

H. de Wijn (Utrecht)

Monochromatic phonons

6 Mar

E. Brezin (ENS, Paris)

Why did we need statistical mechanics to understand quantum field theory?

28 Feb

D. Montgomery (Dartmouth/Eindhoven)

Turbulence and entropy

21 Feb

R.E. Goldstein (Princeton)

The geometry of nonlinear dynamics from Turing patterns to superconductors

14 Feb

V. Gribov (Landau Inst./Budapest/Bonn)

Physics of quark confinement

31 Jan

H.J. Hilhorst (Orsay/Leiden)

Spin glass theory in low dimensions

17 Jan

M. Dogterom (AT&T Bell Labs, Murray Hill)

Physical aspects of microtubule growth and mitotic spindle formation

Colloquium Ehrenfestii in 1995

13 Dec

A. Weis (MPI, Garching)

Atoms in Helium crystals: ".... and what if time would go backwards?"

29 Nov

J. Engelen (NIKHEF)

Electron-proton scattering at high energy and the re-appearance of the Pomeron

15 Nov

W. Schleich (Ulm, Duitsland)

Quantum phase

1 Nov

M. Nauenberg (Santa Cruz/UvA)

Discovery of the laws of orbital motion: Newton, Huygens and Hooke; Solution of a 300 year old puzzle

4 Oct

R. Snieder (Utrecht)

Imaging the interior of the earth

13 Sep

F. Haake (Essen)

From superfluorescent pulses to a superradiant laser

7 Jun

V. J. Emery (Brookhaven National Laboratory)

Collective charge transport in high temperature superconductors

17 May

B.L. Altshuler (NEC/MIT)

Universalities: From Anderson Localization to Quantum Chaos

19 Apr

L. Faddeev (St. Petersburg/Utrecht)

Quantization, what is it?

22 Mar

C. van Haesendonck (Leuven/UvA)


8 Mar

H. Salemink (IBM-Zürich)

Atomic-scale investigations on semiconductor nanostructures: Composition and Doping

1 Mar

N.D. Mermin (Cornell/Leiden)

Reinventing Crystallography: The symmetry of aperiodic crystals

22 Feb

N.J. Lopes Cardozo (FOM, Rijnhuizen)

Filamentation of hot plasma in a magnetic field

15 Feb

J. Blatter (ETH-Zürich)

Vortices in high temperature superconductors

25 Jan

M. Veltman (Ann Arbor/Nikhef-H)

Do black holes exist?

Colloquium Ehrenfestii in 1994

14 Dec

G. Aeppli (AT&TBell Labs, Murray Hill)

From magnets to superconductors with hot and cold neutrons

30 Nov

W. van de Water (TU-Eindhoven)

Spatio-temporal chaos

16 Nov

G. Björk (Royal Inst. of Tech., Kista, Zweden)

The physics of semiconductor microlasers

2 Nov

F.Y. Wu (North Eastern Univ., Boston/UvA, Amsterdam)

Knot theory and statistical mechanics

19 Oct

J.-M. Lévy-Leblond (Nice)

Quantum effects at large (how to build a big world out of small constants)

12 Oct

M. Spiro (DAPNIA, Saclay)

Recent results from the EROS experiment on the search for dark matter (MACHO's)

21 Sep

R. Dijkgraaf (UvA, Amsterdam)

The unreasonable effectiveness of physics in modern mathematics

7 Sep

B. Poelsema (Universiteit Twente)

Manipulation of layer-by-layer growth in metal epitaxy

1 Jun

G. Hadziioannou (Groningen)

Computational devices from soft materials. Is that possible?!

11 May

H. Meyer (Duke, North Carolina)

Equilibration near the liquid-vapor critical point: relevance to microgravity experiments

27 Apr

C. Caroli (Paris VII)

Solid friction as a nonlinear physics problem: stick-slip and creep

20 Apr

J.R. Dorfman (Maryland/Utrecht)

Long range correlations in fluids: theory and experiment

30 Mar

I.K. Yanson (Kharkov, Ukraine/Leiden)

Electrons passing through a point contact in a magnetic field

16 Mar

W.E. Moerner (IBM research, San José/ETH, Zürich)

Spectroscopy of individual molecules in solids

23 Feb

D. Frenkel (AMOLF, Amsterdam)

Solids that boil, liquids that don't

9 Feb

J.J. Koenderink (Medische Fysica, Utrecht)

Pictorial relief

26 Jan

J. Smit (UvA, Amsterdam)

How effective is the Standard Model?

12 Jan

J. Kaastra (Ruimteonderzoek, Leiden)

Massive binary black holes in galactic nuclei

Colloquium Ehrenfestii in 1993

8 Dec

J. van Ruitenbeek (Leiden)

Building electrical contacts atom-by-atom

1 Dec

M. Lüscher (Desy, Hamburg)

Random numbers and deterministic chaos

17 Nov

S. Balibar (ENS, Parijs)

Cavitation in an ultra pure liquid

3 Nov

S. Keiding (Odense University, Denemarken)

Teraherz electronics and far-infrared optics

27 Oct

M.E. Fisher (Maryland, USA/Leiden)

The Saga of Coulombic Criticality: Debye-Hückel, Bjerrum, and Beyond

6 Oct

J. Frenken (AMOLF, Amsterdam)

Surface dynamics and phase transitions studied with ion scattering and high-speed high-temperature STM

29 Sep

P. Kelly (Philips, Eindhoven)

Parameter-free calculations of the properties of materials (Bumble-bees which DO fly)

15 Sep

G. 't Hooft (Utrecht)

Black Holes in Elementary Particle Physics


History of the Colloquium Ehrenfestii

From a document dated 16 December 1985, prepared by Piet Kasteleyn at the occasion of handing over his colloquium duties to Henk Hilhorst, we can reconstruct some of the history of the colloquium Ehrenfestii.
The colloquium was initiated by Paul Ehrenfest, most likely immediately or soon after he came to Leiden (1912), following the example of Boltzmann's colloquium in Vienna. The colloquium was held on Wednesday evenings, in any case from 1926 as people can recollect, but maybe from the beginning. In the sixties it has been tried to shift the colloquium to the daytime, but the disadvantages outweighed the advantages.

In the twenties Ehrenfest started to ask the most important speakers at the colloquium to put their signature on the wall. This was in the old building (corner Zonneveldstraat - Langebrug) where theoretical physics was housed and where the mathematics lectures were held. The building was also called "Leeskamer Bosscha", after the mathematics and physics library there. (In addition Ehrenfest would ask those that stayed at his home to sign the white wall in the guest room of his house, at Witte Rozenstraat 57; also the wifes would sign this wall, and they would sign every time they would come, not only once as in the colloquium room. This wall is [probably] still preserved.) After the war, also other important visiting scientists (in particular mathematicians) that gave a talk in the colloquium room, but did not speak at the colloqium Ehrenfestii, would sign the wall.

The old building was taken down around 1962, to make room for the new wing of the Kamerlingh-Onnes / Instituut-Lorentz complex. Under the guidance of the university archeologists the piece of wall with the signatures was sawn out and stored at the State museum of Antiquities in Leiden, after which it was cemented back into the wall of the new colloquium room. While building the new complex, the Instituut-Lorentz was housed in a wooden barrack on the lawn in front of the Kamerlingh-Onnes laboratory. The signatures of that period were put on the wood which may have been saved but was not incorporated in the new wall (a photograph of the corresponding list of signatures of Lorentz-professors was [and still is] incorporated in the wall).

In the days of Ehrenfest, the colloquium was very renowned. Ehrenfest was famous for the way he led the colloquium. He tolerated no obscurity what so ever, asked questions that coached the speakers in a better presentation and summarised the talk afterwards so well (as people said) that some speakers only then understood what the essence was of what they talked about. Ehrenfest encouraged students to ask questions and denied the existence of "stupid" questions. Students that skipped a colloquium could expect a reprimand.

After Ehrenfest died in 1933, H.A. Kramers took over. In his time the colloquium, including discussions, often lasted until 10 pm. It is likely that Kramers was the one who introduced the name colloquium Ehrenfestii (in the beginning spelled incorrectly as Ehrenfesti). After Kramers died in 1952, S.R. de Groot led the colloquium (and institutionalised the Instituut-Lorentz for Theoretical Physics), until he left in 1964 to Amsterdam.

More on the history can be found in an excerpt from M.J. Klein's biography of Ehrenfest, "Physics in the Making". The documented list of speakers goes back to 1953(!), and can be found on the colloquium homepage. Below is the reconstructed list of organisers of the colloquium Ehrenfestii. November 1998 the colloquium moved from the old Kamerlingh-Onnes laboratory in the center of town, to the new Oort building on the science campus. The signature wall has been moved as well (now in a free-standing structure) and the tradition of speakers signing the wall has been continued on its back side. The last to sign at the old location was G. Veneziano on 27 May 1998, the first to sign on the back at the new location was W. Ketterle, 4 November 1998.

Pictures of the cutting of the wall from Leidsch Dagblad, 4 September 1998 and Mare, 10 September 1998, as well as of the restauration after the move NRC Handelsblad, 2 December 1998, and the new completed structure NRC Handelsblad, 2 December 1998.