Collaborators and friends

Many people with whom I have collaborated with over the years are important to me, as they have become personal friends. Here are some of the most important ones in alphabetical order, but keep in mind that there are too many to list all of them here.



D. P. Aalberts
Even those who did not collaborate with him remember Daniel's stimulating presence as a postdoc in Leiden from 1994-1996. As an assistant professor at Williams College, Daniel has moved more and more into biophysics, and we have continued to collaborate on the fast isomerization of rhodopsin.

C. W. J. Beenakker
I have the fortune of being a colleague of Carlo at the Instituut-Lorentz now, but few people know that we share the same thesis advisor (Peter Mazur), and that we have a joint publication on hydrodynamic interactions of spheres near a wall. Since we share the same thesis advisor, you can check my scientific ancestors by checking the PhD family tree that Carlo traced.

M. Berry
Sir Michael Berry spent two month in Leiden in the fall of 1999. During this time, we started discussing the problem of fractal intensity profiles in unstable mode resonator lasers - my colleagues Eliel and Woerdman in the quantum optics group had just discovered this phenomenon. We were able to derive the fractal dimension of these fractal lasers, as well as the crossover to regular scaling behavior at the small length scales.

D. Bonn
In the late nineties I spent some six months at the Ecole Normale Superieure in Paris as a guest of Daniel Bonn. Our collaboration started during this visit: we became interested in the problem of "melt fracture", the fact that during the extrusion of polymers melts or solutions from a so-called die, the extrudate becomes very irregular above a certain threshold velocity. We identified an intrinsic route to this type of behavior: polymer flow through a pipe is nonlinearly unstable at large enough flow rates.

C. Caroli
Christiane and I collaborated on the sidebranching mechanism of dendrites in 1992 (see publication 58). Later, when I visited Paris for a month, we collaborated on the formation of streamer discharge patterns (publications 75 and 77). In many ways, the seeds for the later work on pulled front dynamics with Ute Ebert were laid in collaboration with Christiane.

U. Ebert
While I had vowed not to work anymore on front propagation into unstable states when I came to Leiden in 1991, with Ute, who came to Leiden as a postdoc in 1994, I returned to this old problem after all again. Together we were able to understand essentially every aspect of pulled front dynamics, and we have many new exact results (publications 83, 89 and 91). Earlier, we worked on streamer discharge dynamics together - I enjoy watching this line of research, which Ute now continues at the CWI, from the sideline.

G. H. Gilmer
George's influence on me, both as a colleague and as a friend and human being, has been much more important than the two papers we wrote together would seem to suggest. As a physicist, George's style of combining numerical simulations with insight is still an example for me.

M. van Hecke
After he did his PhD with me in Leiden, Martin and I have continued to collaborate (with Kees Storm) on sources and sinks in travelling wave systems -- see my publications 80 and 86. Martin worked abroad for several years as a postdoc; he spent most of his time at the Niels Bohr Institute, and during has last few years he got involved in granular media experiments as well. In the summer of 2000 he returned to Leiden to start an experimental and theoretical effort in granular media. He has built up a very energetic group since then, and we now often collaborate as colleagues.

P. C. Hohenberg
During my last few years at AT&T Bell Labs, I collaborated intensely with Pierre on coherent structures in the Complex Ginzburg Landau equation. This culminated in our long (by various people called ``monstrous'') paper 52, and in the work together with Boris Shraiman and Hugues Chaté (papers 51 and 53). Although our roads have separated, I still value Pierre's advice as a member of the Advisory Board of the Lorentz Center.

R. Jochemsen and G. Frossati
I enjoy having the opportunity to learn about Helium in Leiden from my experimental colleagues Giorgio Frossati and Reijer Jochemsen. In recent years, I have become actively involved in the interpretation of their experiments on ``dendritic'' melting of polarized 3He crystals.

L. C. Kimerling
The example that Kim Kimerling set as the head of the department that I was a member of during the eight and a half years I worked at AT&T Bell Labs, has shaped my view of how I want to run my own research group and of the atmosphere that we foster at the Instituut-Lorentz in Leiden.

J. M. J. van Leeuwen
Hans van Leeuwen is the one who is responsible for turning me into a theoretical physicist, when as an undergraduate student at Delft in 1976 I had the fortune of working under his supervision (see my publications 1 and 2). I am happy he is now my colleague in Leiden. A few years ago, we collaborated on the fixed node monte carlo method (see publications 66, 68 and 82).

L. A. Peletier
From Bert I have been able to learn first-hand how mathematicians work and think - his work in recent years on the so-called EFK equation grew out of conversation in the train we had years ago, and in 1999 Ute Ebert and I actively collaborate with him on pulled front propagation. Moreover, we have thought an interactive course ("werkgroep") together in the fall of 1999. Bert has also been instrumental in getting the Lorentz Center of the ground - he has often been a sound-board and mentor for me when I was getting stuck as director of the center.

W. van de Water
Willem is one of the few experimentalists in Holland working on nonequilibrium pattern formation. Although we have no joint publications, we meet a few times a year for discussions of the experiments in his group, or of the theoretical work in my group.

C. M. Varma
Chandra Varma spent three months in Leiden in the spring of 2000 as Lorentz Professor. He gave a course on Non-Fermi-Liquid Behavior and proposed to me to make an introductory review out of this. Clearly, Chandra was the intellectual father of this paper, but I did enjoy tremendously the opportunity to learn from him by helping in making the course material into a readable format.

J. D. Weeks
John was initially mostly my mentor when to AT&T Bell Labs in 1982, since I went to do a postdoc with him. When I stayed on as a member of staff at Bell Labs in the same department with him, we became colleagues and friends. Although we wrote sixteen publications together, much of what I learnt from John can not be strictly found in published papers - John taught me how to think physics.

J. Zaanen
As the founding father of ``stripes'' in high-Tc materials, colleague and friend Jan remains the main driving force of the work of this line of research at our institute. While we come from very different backgrounds, scientifically, we have been able to collaborate on this problem very profitably. In the last few years we've both gone our own ways scientifically.


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