Scientific Report for the Lorentz Center workshop on:


Active liquids, 21-25/09/2015


Olivier Dauchot[1] (CNRS, ESPCI-ParisTech, France), Julien Tailleur (CNRS, Paris Diderot Univ., France) Marjolein Dijkstra (UTRECHT Univ., Netherlands) Sriram Ramaswamy (TIFR Centre, Hyderabad, India) John Toner (Univ of Oregon, United States)


Goals and Methods

Active liquids are composed of large assemblies of active “particles”, the defining feature of which is that energy being injected at the level of the individual particle promotes self-propulsion and other non-equilibrium features. The recent upsurge of studies has led to a rather confusing situation where many competing theories, incompatible as often as not, try to explain experimental or numerical results. The goal of the meeting was to confront all the fruitful approaches and try to identify major issues on which the Active Matter community should focus in the future.


To achieve this goal, we had organized the workshop around review Duet-Lectures, andQuestalksselected on the basis onQuestract”, to load the focus-topic discussions. The questalks and related questracts was a complete new format: participants had to present and discuss questions of interest to them rather than results. The participants also had the opportunity to present their work with posters. The last day of the meeting was left open to a special synthesis and perspective session.



Overall the workshop was a complete success as could be inferred from the very positive feedback we had from the participants. Many of them went back to their home institution, with new perspectives in mind.


The new comers to the field could learn very efficiently during the morning review duet-talks, a fact that could be appreciated during the questions and focus discussion sessions.  This new format was challenging for the speakers, who all made the effort to provide integrated performance. (We had carefully taken care of strongly encouraging them not to do two separate talks)


The new Questalk format appeared to be extremely efficient in launching the discussions sessions All were extremely animated and vivid. The debates lasted far beyond the anticipated schedule. An entire new topic, un-anticipated at the time of the preparation of the workshop and which had emerged a few months before the workshop was intensively debated during the whole week. Two participants spontaneously prepared a review talk during the week to be presented on the Friday morning.


The “wikipedia night” during which we started editing the wikipedia page on Active Matter was also a success: both in terms of outcome and as a new form of scientific proceeding.


All in all this workshop was very successful, both thanks to the scientific quality of the audience and the great format allowed by the Lorentz Center.

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