## Former postdocs

dr. M. Horbach

Marc did his PhD with Gerd Schön in Delft. He then worked in Leiden as a postdoc from 1991-1993. We collaborated on marginal fermi liquid theory (see my publications 59 and 63) and on fluctuation effects in the highT_{c}'s (publications 50, 60 and 71). Marc went on to Rutgers to do a postdoc with Andrei Ruckenstein, and then decided to take a job with Information Builders on Manhatten. Since a few years he is teaching at Sussex County Community College.

prof. D. P. Aalberts

Daniel came to Leiden after completing his PhD at MIT with N. Berker. In Leiden we started to collaborate, together with graduate student Ferry Vos, on understanding the fast isomerization of rhodopsin. As a professor at Williams College, Daniel then became the main driving force behind this work. See my publications 72, 73, 79 and 90 or Daniel's homepage for more information.

dr. H. Eskes

Henk did his PhD with G. Sawatzky in Groningen. He then worked at the MPI für Festkörperforschung in Stuttgart as a postdoc before coming to Leiden in 1994 to work with Jan Zaanen and me on the physics of charged domain walls in relation to the highT_{c}materials. We worked extensively together on the statistical physics of so-called lattice strings, see my publications 74, 76 and 85. Henk now works at the Dutch meteorological institute KNMI on the ozone problem, work he enjoys very much. Actually, several people who graduated at our institute or did a postdoc here, afterwards made successful careers at the KNMI.

prof. U. Ebert

Ute came to Leiden in 1994 after doing her PhD in Essen on polymer dynamics with L. Schäfer. We collaborated both on streamer discharge dynamics (see my publications 75 and 77 or the general writeup) and on the universal relaxation properties of so-called pulled fronts which propagate into a linearly unstable state (publications 83, 89, and 91 or the general overview and press release). Since September 1998 Ute is a staff member of the CWI (Centrum for Wiskunde and Informatica) in Amsterdam. Amoung other things, she has built on the work we started in Leiden on streamers to study various forms of discharge dynamics. Her group has branched into various directions, mostly associated with pattern formation in plasmas. In 2002, Ute was also appointed as a professor at the Technical University of Eindhoven, where she spends one day a week.

dr. A. van Otterlo

Anne had done his PhD with G. Schön in Karlsruhe, and then worked as a postdoc with G. Blatter in Zürich and G. Zimanyi at Davis before coming to Leiden in 1997 as a postdoc of Jan Zaanen and me. Soon afterwards, he obtained a prestigious FOM ``springplankplaats'', but in the end he decided to take his life into a different direction. He took a job at Lucent Technologies in Hilversum, the Netherlands; he was very happy there till Lucent got in trouble, and then moved to Siemens in The Hague.

dr. G. Tripathy

Goutam got his PhD from the Tata Institute in Bombay on driven diffusive systems. Goutam joined us in August 1998, and went back to India in September 2000. During Goutam's stay in Leiden, we have been studying fluctuating pulled fronts, motivated by the observation that the 1/t power law relaxation of the velocity of planar pulled fronts is likely to give rise to a new universality class for fluctuating pulled fronts. One of our remarkable discoveries/contentions is that unlike most "normal" fronts that separate a stable from a metastable state and which are in the KPZ universality class when they are fluctuating, fluctuating "pulled fronts" are not in the standard KPZ universality class. In fact, together with Andrea Rocco and Jaume Casademunt, we conjecture that they are in the universality class of the KPZ equation in one dimension higher than one would naively expect. E.g., according to our results the scaling of a one-dimensional pulled front is given by the 2+1D KPZ equation rather than the 1+1D KPZ equation. See my writeup for details or our paper. Goutam is presently a professor at the Institute of Physics in Bhubaneswar, India.

dr. J. Müller

Judith got her PhD at the McGill University in Montreal in 1998 on a phase field model for the study of the Grinfeld instability of crystal surfaces under stress. Since Judith joined us in in Leiden in, we have been studying biophysics and in particular interfacial dynamics in bacterial growth models. The most popular model for growth of a bacterial colony, introduced by Ben-Jacob and coworkers in Israel, gives a bacterial density which is a singular function of the spatial coordinate. As a result, standard stability methods fail, but Judith and I have been able to get around this problem and study the linear stability of fronts in such models. In July 2001, Judith left us to take a job at Motorola company in Austin, Texas.

dr. A. Gama Goicochea

Armando got his PhD in 1998 at Stanford University on the long range proximity effect due to pair echos (related to Andreev reflection). In April of 1999 he came as a postdoc to Leiden on a joint position of Jan Zaanen and me in the field of correlated systems (stripes). Armando has been mostly working in collaboration with Jan. Armando is now a staff scientist at the Centro de Investigacion en Polimeros in Mexico.

prof. Z. Nussinov

Zohar Nussinov joined the groups of Jan Zaanen and me in Leiden, after doing his PhD in 2000 at UCLA with Steve Kivelson. Zohar has a very broad range of interests: glasses, strongly correlated systems, single spin dynamics, orbital problems and statistical physics. With Jan he published several important papers on the physics of stripes in high Tc superconductors. During Zohar's stay in Leiden, Chandra Varma spent three months as Lorentz Professor in Leiden. He invited Zohar and me to assist him in writing a review paper on Non-Fermi Liquid behavior for Physics Reports. Zohar went on to work at Los Alamos National Laboratory as a postdoc, and then found a job as assistent professor at the Washington University in St. Louis.

dr. D. Panja

Debabrata joined our group as a postdoc in September 2000, after recieving his PhD in August with Bob Dorfman at the University of Maryland in the USA. His PhD was on kinetic theory approaches for understanding chaos (Lyapunov exponents) in molecular systems (part of this work was done in collaboration with Henk van Beijeren and Ramses van Zon in Utrecht). In Leiden have collaborated on a variety of problems, in particularon fundamental properties of fluctuating fronts. After leaving Leiden, Deb spent two years as a postdoc in Amsterdam. During this time he wrote a nice review on the problem of fluctuating fronts, and in addition he started working on granular media. In 2004, he moved on to Utrecht University, where his interests broadened to the theory of glasses and the statistical physics of translocation. Since the fall of 2005, he is a member of the Oceanography group at KNMI, the Dutch meteorological research center. In October 2007, Deb joined the Akzo Nobel research center in Sassenheim, the Netherlands. As of May 2016, Deb is an assistant professor in the Computer Science department of Utrecht University.

prof. M. J. Howard

Martin's career started in Oxford, where he did his PhD with John Cardy. He then went to the Niels Bohr Institute in Copenhagen, where collaborated, amoung others, with Martin van Hecke, who had also gone there after he obtained his PhD in Leiden. Before joining us in Leiden in September 2001, Martin also stayed for a year at Virginia Tech in Blacksburg, U.S.A. and two years at Simon Fraser University in Vancouver, Canada. In Vancouver, he got interested in a problem of protein diffusion in bacteria, in particularE. coli. Together with Andrew Rutenberg from Dalhousie University, he developed a very nice model that allows one to understand many of the experimental observations on the time dependens of protein concentrations in these bacteria. Martin moved to Imperial College with a Royal Society fellowship in 2002. In 2005 he was promoted there to reader. Since August 2007, he is a Royal Society University Research Fellow and Project Leader at the John Innes Centre for plant science and microbiology, where he is presently director and full professor.

dr. R. Folch

Roger did his PhD with Jaume Casademunt in Barcelona on phase field models of crystal growth. He then moved to Paris, where he worked both at the Universite Paris VI at Jussieu and at the Ecole Polytechnique. In collaboration with Matthias Plapp from the Ecole Polytechnique he worked in particular on introducing a phase field model for eutectic growth - the need to extend existing models to three phases gives a number of new challenges. Roger spent two years with us from 2002 till 2004. He mostly continues his work on phase field models with Plapp, but we also did some joint work on fingering phenomena in chemical reactions. After a short stay at the MPI-PKS in Dresden as a postdoc, he became a staff member at the Universitat Rovira et Vigili in Tarragona, Spain.

prof. E. Somfai

Ellák received his PhD with Len Sander at the University of Michigan in Ann Arbor in June 1999, and started as a postdoc in Leiden in September 1999. We worked on statistical physical aspects of granular flow. One of the topics we looked at is the statistics of shock waves, and this lead to a very interesting paper on sound waves in granular media. Soon after Ellák came to Leiden, we also started to collaborate very fruitfully with Raoul van Gastel and Joost Frenken from our experimental condensed matter group, on vacancy-induced diffusion at surfaces. See e.g. The atomic slide puzzle for a short writeup on this. In July 2001, Ellák went to the University of Warwick with a Marie-Curie fellowship. He returned to Leiden in May 2003 on a EU network position. During his second stay in Leiden, Ellák contributed a lot to almost every granular media project, as he developed the numerical code to generate our packings and to study the density of states of the vibration/torsion modes. A second new research projects that Ellák took up back in Leiden is the the extension of so-called Dissipative Particle (DPD) Models to viscoelastic fluid flow, like polymer flow. The idea is that one can simulate polymer rheology simply with a DPD-type model of dumbbells In September 2005 Ellák moved on to Oxford University. In December 2007 Ellák became faculty member at the University of Warwick in the UK. He is now with the Wigner Research Centre for Physics in Budapest.

dr. B. Ashok

Ashok got his PhD in the summer of 2004 at the University of Massachussetts at Amherst, where he worked with Muthukumar on various topics in the area of polymer dynamics (rheology of wormlike micelles, dynamics of polymers in shear flow, etc.). He worked in Leiden from the fall of 2004 to the spring of 2006 on the subcritical instabilities of polymer pipe and Couette flow. Ashok is now in back in India, where he has a faculty position at the Advanced Centre for Research in High Energy Materials at the University of Hyderabad.

dr. K. Shundyak

Kostya got his PhD in the summer of 2004 in Utrecht, where he worked with van Roij on the theory of interfaces and wetting in hard rod nematics. He came to Leiden in the fall of 2004 to work with Martin van Hecke and me on granular media. One of the nice things that Kostya showed was that in frictional packings a significant fraction of the bonds are at the Coulomb threshold, and that if these bonds are considered contrained (rather than arbitrary) then gently prepared frictional packings do approach a generalized isostaticity line close to jamming. In 2006, Kostya moved to AMOLF to do a postdoc in biophysics with Bela Mulder. Since September of 2009, he is leading on the validation of various financial models for the Dutch bank ABN-AMRO.

dr. M. Depken

Martin Depken got his PhD in August of 2003 at Oxford University in the UK. His PhD work included a nice analysis of a simple model for the effect of tapping on granular media, which gives the logarithmic relaxation also observed experimentally. In addition, he has worked on asymmetric exclusion processes. In Leiden Martin developed a new framework to describe and analyze wide shear zones in granular flow, in particular the granular flow behavior observed by Denis Fenistein and Martin van Hecke in their experiments on shear in a Couette cell with split bottom. Martin's approach leads to a few nontrivial predictions that were later confirmed by extensive computer simulations. In addition, Martin started to work with biophysicist Helmut Schiessel, while in Leiden. After his stay in Leiden, Martin completely concentrated on biophysiscs: From 2006 till 2008, Martin was a postdoc with Frank Juelicher at the Max Planck Institute in Dresden, and from 2008 till 2011 with Fred MacKintosh at the Vrije Universiteit in Amsterdam. As of the fall of 2011, he holds a tenure track position in the Bionano Department of the Technical University of Delft.

dr. A. N. Morozov

Alexander got his PhD in February 2002 in the group of Hans Fraaije at the University of Groningen. His PhD research was on the ordering dynamics of block copolymers. One of the nice results he obtained was the influence of shearing on the ordering of block copolymers: he showed that shearing enhances the tendency to order, contrary to what one might have expected, namely that shearing would "mix" the molecules more and hence suppress the tendency to order. Alexander has worked with me on several pattern formation issues, in particular on the origin of polymer flow instabilities in processes like melt fracture. By performing a weakly nonlinear amplitude expansion of Couette and Poiseuille flow of a polymer melt, we have been able to show that the flow is linearly stable but nonlinearly unstable (a so-called "subcritical transition"). This scenario, which recently has been confirmed by numerical simulations of other groups, is of quite some fundamental importance. In January 2007, Alexander moved to Edinburgh, where he obtained a prestigious Royal Society of Edinburgh fellowship. He is now on the faculty of the University of Edinburgh.

dr. E. Sultan

Eric started in November 2005 in Leiden, after he got his PhD at the ENS in Paris. He did his PhD work under supervision of Martine Ben-Amar on evoration/marangoni instabilities in thin films. In Leiden worked with Alexander Morozov, Jan-Willem van de Meent, Ellák Somfai and me on developing a DPD-type model for polymer rheology. This model is a versatile way to simulate visco-elastic flows: the orientation distribution of the dumbbells in this model is quite consistent with results for a single polymer in a shear flow, while this fluid exhibits all the normal stress effects of a polymer fluid. In November 2007, Eric moved back to Paris as a postdoc at the Universite Paris VII, and in September 2008, Eric he took a position as Maitre de Conference at the Université Paris-Diderot (Paris VII).

B. Tighe

Brian got his PhD with Joshua Socolar at Duke University in the USA in the summer of 2006. The topic of his PhD research was force correlations (force chains) in static granular media. One of the contributions Brian made was to invent a smart monte carlo move ("wheel move") that allows one to sample very effectively the states in the so-called force ensemble for granular matter. This allowed him to unravel many questions concerning the force distributions. Brian joined us in Leiden in October 2006. Brian is working on dynamic properties of granular matter, amoung other things, and on the rheology of foams as well. In 2009 he obtained a national VENI grant, which allowed him to start in Leiden as an independent reseracher. In October 2011 Brian moved to the Mechanical Engineering department at the Technical University Delft, where he is now an associate professor.

S. Henkes

Silke got her PhD with Bulbul Chakraborty at Brandeis University in the USA in the summer of 2008. One of the main topics of her thesis was the development of a theory for the distributions of stresses in granular media at the coarse grained level, so for clusters of particles. In Leiden Silke is now working with several of the group members on the properties of frictional granular packing. Preliminary results of Silke show that if the fact that a finite fraction of forces is fully mobilized is taken into account, the granular packings do have an enhanced density of states near jamming at any value of the friction coefficient. In the fall of 2010, Silke returned to the USA as a postdoc in Syracuse. As of 2013, she holds a Senior Lecturer position at the University of Aberdeen.

## Former graduate students

H. J. M. van Bemmel

thesis:Real Space Aspects of Correlated Fermions(1995).

After being a highschool physics teacher for a couple of years, Hans was the ``instituutsmanager'' (executive director) of the Lorentz Center from the summer of 1998 till September of 2000. This period was a crucial phase in the buildup of the Lorentz Center, but it also made Hans realize that his heart was really with teaching physics, not with management. In September 2000, he therefore accepted a part time job as a high school teacher in Leiden, and a part time job at the Amstel Institute of the University of Amsterdam, where he is involved in developing new teaching programs for the sciences. Since about 2005, Hans has returned to full time teaching at highschools.

E. G. T. Bosch

thesis:An Experimental Investigation of Faraday Waves and Spatio-Temporal Chaos(1995).

As Eric did his experimental work at the University of Eindhoven under the supervision of Prof. Willem van de Water, I was only a distant observer in his thesis work. Eric now works at the Philips Research Laboratory.

M. L. van Hecke

thesis:The Amplitude Description of Nonequilibrium Patterns(1996).

Martin worked with me on various application of amplitude equation description of pattern forming systems. Two particular systems we studied was the traveling waves in rotating Rayleigh-Benard experiments and, together with Kees Storm, the formation of sinks and sources in the traveling waves that occur near a heated wire suspended in a fluid. After obtaining his PhD, Martin spent four years as a postdoc at the Niels Bohr Institute/CATS and the MPI for Complex Systems in Dresden. Initially he continues mostly on chaos in pattern forming systems (he is the father of the so-called "homoclon solutions"), but during his last year in Copenhagen Martin also started to do experiments on granular media, and he has returned to Leiden in the summer of 2000 to set up an experimental and theoretical program on granular media. Since the summer of 2003, he holds a tenured faculty position in Leiden, and in May 2008 he was promoted to full professor.

F. L. J. Vos

thesis:On fermionic correlations in high-T_{c}superconductors and molecular systems, (1998).

Ferry was a "pioneer" in the sense that he was one of the first physicists that got a job at at CMG (Computer Management Group) in Holland. As soon as CMG discovered that physicists like Ferry can be very valuable at a company like this, he was also made recruiter. So he visited us several times a year to see who he could steal away from our Institute. In late 1999, Ferry moved toOptiver in Amsterdam, a derivatives trading company, as a risk manager, then joined AOT (Amsterdam Option Traders) in September 2002, and as of March 2004 he was Senior Vice President of market risk management at ABN-AMRO in Amsterdam. A few years later, he joined Anthos, the foundation of the richest family of the Netherlans. Lately Ferry has been the driving force behind the plan to start a small econophysics group in Leiden.

M. S. L. du Croo de Jongh

thesis:Density Matrix Renormalization Group Variants for Spin Systems, (1999).

Lucas and Hans van Leeuwen have been doing very nice work on combining the Density Matrix Renormalization Group method with Fixed Node monte carlo ideas: the wave function obtained from DMRG is the guiding wavefunction in a subsequent monte carlo simulation. In practice, I have been essentially an interested spectator in this problem, they did all the real work together. After working for a while for the McKinsey consultancy firm, Lucas joinedOliver Wymanin Zürich as a consultant.

C. Storm

thesis:Dynamics and Interactions of Coherent Structures in Nonlinear Systems, (2001).

Kees studied physics in Leiden, and wrote an undergraduate thesis with me onNumerical and Analytical Studies of Amplitude Equations. He started working with me as an AIO in nonequilibrium pattern formation in the summer of 1997. He has since worked with Martin van Hecke and me on amplitude equations for traveling wave systems, and with Ute Ebert and me on the universal relaxation of coherent and incoherent pulled fronts. In addition, we have worked together with Michael Berry on understanding fractal lasers intensity profiles, following up on an earlier discovery of the fractal nature of unstable cavity lasers in the group of Han Woerdman in Leiden. Kees got his PhD in June 2001; he took a deliberate decision to move into biophysics, so a month later, he left Leiden to become a postdoc at the University of Pennsylvania with Philip Nelson Tom Lubensky, and Paul Janmey at U Penn. In September 2003, Kees moved to Paris to take a postdoc at the Institut-Curie, and he returned to Leiden to join the group of Helmut Schiessel in the fall of 2004. In December 2007, took a faculty position at the Technical University Eindhoven; he is much appreciated in Eindhoven and is now associate professor.

M.-T. Westra

thesis:Patterns and Weak Turbulence in Surface Waves, (Eindhoven, 2001).

Mark Westra did his PhD with Willem van de Water in Eindhoven on experiments on Faraday surface waves and on traveling waves observed near a heated wire. Faraday waves are the standing waves which one can observe if a fluid layer is oscillated vertically on a loudspeaker with frequencies typically in the range 50-100 Hz. Mark and Willem made one of the largests of these setups that exist to may knowledge, which allowed him to study the formation of patterns in these experiments. The work on traveling waves induced by a heated wire a few millimeters below a fluid surface was motivated by the work of Martin van Hecke, Kees Storm and myself (writeup) and resulted in a joint publication. Because of this interaction, I was asked to be officially "co-promotor" of Mark, a Dutch construction to acknowledge interaction of a graduate student with other senior people. Mark is now a public relations and press officer at the FOM Plasma Institute "Rijnhuizen"; he is also a part-time science journalist, publishing in the Nederlands Tijdschrift voor Natuurkunde.

J. H. Snoeijer

thesis:Statistics of Force Networks in Granular Media, (Leiden, 2003).

Jacco got his undergraduate degree at Twente University of Technology in Enschede in 1999; after following the courses to become a physics teacher, he decided to return to research and work with Martin van Hecke and me on granular media. Jacco's first contribution was an important insight into the difference between the distribution of interparticle forces in the buld of a granular medium, and the distribution of particle wall-forces. This difference results from the difference in the packing at the wall. This work also stimulated a collaboration between Jacco and Hans van Leeuwen on the properties of theq-model for granular media. The highlight of Jacco's thesis is a new ensemble theory for this force distribution in granular media, which he developed with Martin van Hecke and Thijs Vlugt. Jacco completed his PhD in September of 2003. He then worked as a Marie-Curie fellow at the ESPCI in Paris and as a postdoc with Jens Eggers in Bristol. In February 2008, he started as a faculty member at Twente University in the Physics of Fluids group of Detlef Lohse. Jacco is now a professor there.

M. Bosch

thesis:Stripes and Cuprate High(Leiden, 2003).T_{c}Superconductors

Marco did his undergraduate studies at the Technical University of Eindhoven in the Netherlands before joining us in the spring of 1997. He worked (as an OIO funded by the research foundation FOM) with Jan Zaanen and me on the statistical physical properties of stripes in the high temperature superconductors. One very interesting result Marco obtained is the suggestion that the leveling off of the inverse stripe distance as a function of doping when the doping level becomes larger than about 1/8, is a result of the occurrence of kinks in the stripes. This suggestion leads to an experimentally testable prediction: these kinks will give rise to a shift in the Bragg peaks of the stripes (there are some experiments which claim to see such an effect). Together with Zohar Nussinov, Marco was also able to give insight into the particular way in which holes condense into stripes. Marco worked at the research lab of the steel company Corus till the fall of 2004, when he joined LogicaCMG, a company in IT services and wireless telecoms. He is now working at Shell Research in Rijswijk, the Netherlands.

C. Baggio

thesis:Dynamics of vortex fronts in type II superconductors(Leiden, 2005).

Chiara got her undergraduate degree at the University of Padova in Italy, but she actually did her undergraduate research at Imperial College with D. Vvedensky; they worked on using Langevin equations for statistical physical growth models. Chiara started in Leiden in the middle of October 2001, and has worked with me on nonequilibrium pattern formation of vortices in superconductors. We studied two aspects: the stability of a front of vortices propagating into a domain of anti-vortices, and the propogation of "vortex fingers". The latter are finger-like domains of high vortex density which rapidly propagate into a thin superconductor if the magnetic field is ramped up. Such patterns were observed in experiments by Welling and Wijngaarden at the Vrije Universiteit in Amsterdam. Chiara developed a nice boundary-layer type model for the propagation of such vortex fingers. You may enjoy a photo galary of Chiara's thesis defense. Since October 2006, Chiara is working for PartnerRe in Zürich, a reinsurance company.

W. Ellenbroek

thesis:Response of Granular Media near the Jamming Transition(Leiden, 2007).

Wouter did his undergraduate studies at the University of Nijmegen, where he worked under supervision of H. Knops. He wrote his undergraduate thesis on the Frenkel-Kontorova model. Since October 2003, he has been working (as an OIO funded by the research foundation FOM) with me and Martin van Hecke on the statistical physical properties of Granular media. Wouter has in particular been studying the linear response of granular packings. It turns out that as one approaches the jamming point, many properties exhibit interesting scaling behavior. Wouter's work gives important new insight in the microscopic mechanism underlying this scaling: the displacement angle distribution which he introduced turns out to be a very powerful way to display and analyze this scaling behavior. From October 2007 till the summer of 2010, Wouter was a postdoc at the University of Pennsylvania in Philadelphia. With the help of a VENI grant he returned to Holland in the fall of 2010, where obtained a position at the Technical University Eindhoven. He is now tenured.

P. Becherer

thesis:Nonlinear dynamics aspects of subcritical transitions and singular flows in visco-elastic fluids(Leiden, 2008).

Paul did his undergraduate work at the Vrije Unversiteit in Amsterdam in the high energy physics group, before joining our group in November 2003. He has been working with us on the unusual aspects of visco-elastic flows. In connection with predictions of Alexander Morozov and me that parallel visco-elastic shear flows exhibit subcritical instabilities, Paul investigated the applicability of higher order amplitude expansion techniques to probe such instabilities. In addition, Paul showed that the elastic stresses at stagnation points in visco-elastic fluids are typically singular, where the nature of the singularity is determined by the symmetry of the flowfield near the stagnation point, and, if applicable, the presence of boundary conditions on the flowfield. In February 2009, Paul started at the Culgi, an international computational chemistry start-up company that is dedicated to providing industry with revolutionary modelling tools for the rational design of soft matter formulations.

Z. Žeravčić

thesis:Vibrations in Materials with Granularity(Leiden, 2010).

Zorana completed her studies in physics at the University of Belgrade in the summer of 2006. She then joined our group to pursue a PhD in granular media research. Together with David Nelson from Harvard, we investigated localization effects in granular packings. In collaboration with Sid Nagel and Andrea Liu, Zorana has studied the jamming scenario in packings of ellipsoids. For frictionless sphere, the rotational degrees of freedom are trivial, but for ellipsoids they are not. By following what happens when spheres are gradually deformed into ellipsoids, Zorana was able to throw new light on the jamming scenario. In addition, with Detlef Lohse she studied the collective dynamics of bubbles in a liquid which are excited by ultrasound. Zorana got her PhD in June 2010, and started as a postdoc in the group of Michael Brenner at Harvard University in the fall of 2010. After a stay at Rockefeller University, she moved to Paris, where she is now an associate professor at the ESPCI.

J.-W. van de Meent

thesis:Making it big: How Characean Algae use Cytoplasmic Streaming to Enhance Transport and Growth(Leiden/Cambridge, 2010).

Jan-Willem did his experimental work as an undergraduate student with Martin van Hecke on granular media; he he contributed significantly to work on wide shear zones and also spent half a year with Clement in Paris. After returning to Leiden he his masters project with Alexander Morozov and me on the applicability of so-called DPD (Dissipative Particle Dynamics) models to simulate turbulent flows: DPD simulation were shown by him to be powerful enough to study weak turbulence in a compressible fluid. In september 2006, Jan-Willem started in Cambridge to pursue a PhD jointly with Ray Goldstein and me. He is working on cytoplasmic streaming. One of Jan-Willem's contributions to the field is that he analyzed the streaming flow in Characean Algae in detail, and was able to show that MRI velocity measurements confirm his flow predictions very well. Jan-Willem received his PhD in September of 2010, and then became a postdoc at Columbia University. In the fall of 2016, he will start at Northeastern University as an assistant professor in Computer Science.

Erik Woldhuis

Erik Woldhuis joined the group in September 2007 as a master student. Together with Brian Tighe and me he investigated to what extent the so-called spot model for the quasistatic flow of granular media can be extended to understand the wide shear zones in granular media discovered in recent years in the group of Martin van Hecke. After obtaining his masters degree in June 2008, Erik stayed as a graduate student of Martin van Hecke and me. When I moved to FOM, he worked under direct supervision of Martin van Hecke. Erik is presently a teaching at a highschool.

## Former undergraduate students

J. D. Balkenende

undergraduate thesis:Het Tomonaga-Luttinger model(1992).

F. L. J. Vos

undergraduate thesis:On the existence of oscillatory pulse solutions in the complex Ginzburg-Landau equation, (1992).

Ferry went on to do a PhD with me in Leiden (see above).

C. Langeveld

undergraduate thesis:Modelling Mechano-Electric Feedback in Cardiac Tissue(1992).

Cor went on to do a PhD at the Agricultural University Wageningen in the Netherlands.

E. de Wit

undergraduate thesis:Investigations of a complex Ginzburg-Landau equation(1995).

C. Storm

undergraduate thesis:Analytical and Numerical Studies of Amplitude Equations(1997).

Kees went on to do a PhD with me in Leiden (see above).

W. Spruijt

undergraduate thesis:Non-perturbative Dynamics of Pattern Generating Fronts(1998).

Soon after getting his physics degree, Willem also obtained a law degree.

B. Meulenbroek

undergraduate thesis:Nonlinear amplitude expansion for Melt Fracture(2001)

Bernard went to the CWI in Amsterdam to do a PhD under the direction of Ute Ebert. He now holds a teaching position at the Technical University Delft.

H. de Haan

undergraduate thesis:A study of Vortex-Antivortex fronts in Type-II superconductors(2003)

Hans initially took a job just to look around, but then decided to do a PhD in the social sciences at the Dutch Research Institute for Transitions at the Erasmus University in Rotterdam. He defended his thesisTowards Transition Theoryin September 2010, and then went on to do a postdoc in the Policy Analysis section at the faculty faculty Technology, Policy and Management of the Erasmus University.

T. Idema

undergraduate thesis:Subcritical transitions in the parallel-plate flow of viscoelastic fluids(2004)

Timon studied both mathematics and physics, and obtained master degrees in both. He then did a PhD with Kees Storm (see above) and Helmut Schiessel in our biophysics group. After obtaining his PhD in December 2009, he became a postdoc at the University of Pennsylvania.

J.-W. van de Meent

undergraduate thesis:Onset of turbulence in a model geometry

Jan Willem went on to do a PhD jointly with Ray Goldstein (Cambridge) and me (see above).

Giovanni Lanzani

undergraduate thesis:A Phase Field Model for Supercooled Glycerol

Giovanni came from Italy to Leiden through the Erasmus program; he did his masters project in collaboration with Joris Remmers, Kees Storm and me, and is presently a PhD student in the group of my colleague Helmut Schiessel.

[Students and postdocs] [Collaborators] [Wim van Saarloos] [Instituut-Lorentz]