Scientific report

Scientific coordinators:
Andreas Deutsch (Technische Universität Dresden, Germany)
Guy Théraulaz (Research Center on Animal Cognition, Toulouse, France)
Tamas Vicsek (Eötvös Loránd University, Budapest, Hungary)
Organisation:
Katrin Lantsch (Max-Planck-Institut für Physik komplexer Systeme)

Main focus
Research on collective motion had arrived at a stage where it deserved its own dedicated meeting, the first of its kind. It can be assumed that there must be a number of unifying principles connecting the spectacular manifestations of ``moving together" in living systems, being one of the most relevant manifestations of collective behavior in nature, and that the corresponding big picture is likely to emerge from a meeting like the COLMOT workshop in Dresden. One important goal of the workshop was, and it has indeed been achieved that the meeting was attended by the best theoreticians, experimentalists and modelers, physicists, biologists, and mathematicians working on the subject. In particular, I. Couzin, R. Goldstein, H. Chaté, C Marchetti, S. Ramaswamy and D. Sumpter are worldwide acknowledged leading specialists in their field. Beyond new theoretical insights fascinating examples of collective motion were presented at the workshop including systems ranging from cultures of migrating tissue cells to ant colonies and flocks of birds.

Invited speakers
Ezequiel Albano (Universidad Nacional de La Plata, Argentina), Markus Bär (Physikalisch-Technische Bundesanstalt, Germany), Eshel Ben-Jacob (Tel Aviv University, Israel), Hugues Chaté (CEA Saclay, France), Iain Couzin (Princeton University, USA), Andras Czirok (University of Kansas, USA & Eötvös University, Hungary), Jacques Gautrais (Université Paul Sabatier, France), Irene Giardina (Università Roma 'La Sapienza', Italy), Raymond E. Goldstein (University of Cambridge, UK), Carl-Philip Heisenberg (Max-Planck-Institut für Molekulare Zellbiologie und Genetik, Germany), Charlotte K. Hemelrijk (Rijksuniversiteit Groningen, The Netherlands), M. Cristina Marchetti (Syracuse University, USA), Mitsugu Matsushita (Chuo University, Japan), Fernando Peruani (Max-Planck-Institut für Physik komplexer Systeme, Germany), Sriram Ramaswamy (Indian Institute of Science, India), Lutz Schimansky-Geier (Humboldt-Universität zu Berlin, Germany), Christian Schmeiser (Universität Wien, Austria), David J.T. Sumpter (Uppsala University, Sweden)

Summary of contributions
The conference benefited significantly from the clear efforts of the speakers to make their topic of research understandable to the highly interdiciplinary audience. The majority of the invited speakers had a mathematical/physical background but keynote speakers included also biologists (e.g. Carl-Philip Heisenberg, Charlotte K. Hemelrijk). Theoretical topics focused on "Evolution of collective behavior" (Ian Couzin), "The order of the flocking transition" (Sriram Ramaswamy), "Derivation and stability of hydrodynamic equations for self-propelled particles" (Eric Bertin), "Fluctuations in self-propelled particles" (L. Schimansky-Geier), "Collective decision making" (Larissa Conradt), "Collective behavior in large groups" (Francesco Ginelli), "Modelling active fluids" (M. Cristina Marchetti), "Structural properties of networks formed upon swarming" (Ezequiel Albano), "Minimal models for collective motion" (Hugues Chate), "Clustering, spatial patterns and information spreading in self-propelled particle systems" (Fernando Peruani). Biological examples of collective behavior covered bacteria (Markus Bär, Mitsugu Matsushita, Masayasu Mimura), cell cultures (Andras Czirok, Inbal Hecht, Carl-Philip Heisenberg), bird flocks (Kunal Bhattacharya, Charlotte K. Hemelrijk, Irena Giardina), fish swarms (Jacques Gautrais, David Sumpter), ants (Andrea Perna), and locusts (Jan Haskovec).

The workshop featured a distinguished colloquium talk by Raymond E. Goldstein on "Microfluidics of cytoplasmic streaming" and a very interesting movie session (Collective Minds: The Intelligence of Swarms, ARTE, 2009 with contributions by Guy Theraulaz).

Contributions by young scientists
Plenty of space was given to young scientists to present their work either in the form of posters (we had 33 poster contributions) or giving talks in the workshop itself. In fact, 15 talks were reserved for young scientist who are either still doing their PhD or are at an early post-doc stage. The newcomers had no problem to fill the allocated time of 45 min with striking research ranging from theoretical problems as "The phase diagram of migrating cells" (Christophe Deroulers) and "Onset of collective motion due to escape and pursuit" (Pawel Romanczuk) to practical/biological considerations "From passive to active navigation: how a cell can find its way" (Inbal Hecht). The "newcomers" had a lot of chances to interact and they indeed did with the leaders of the field.

Scientific results
The main benefit of this workshop was certainly to discuss the latest scientific results and, furthermore, that people with different physical/mathematical and biological origins got to know each other who would not have met otherwise. Intense discussions after the talks and in the lunch and coffee breaks were a workshop hallmark and there was a general interest to get to know more about each others problems and ideas. A great opportunity to strengthen interactions was provided by the workshop dinner and the workshop excursion including a guided tour through the old town of Dresden with a life demonstration of the famous Silbermann organ at the Cathedral by cathedral organist Thomas Lennartz. In general, presentations of new theoretical results and recently gained deep insight into striking biological examples of collective behavior impressed the 'collective behaviour' community and the organizers are already a workshop follow-up within the next two years. Furthermore, a special issue on "Statistical Physics and Biology of Collective Motion: from Cells to Organisms" is under preparation. This will contain a selection of the Colmot workshop presentations. In conclusion, the COLMOT Workshop has the potential of launching a new field of activity and a series of related conferences.

For further information please e-mail to: colmot10@pks.mpg.de