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Wednesday, May 14

  1. page Talks & Discussions edited ... Cilia-driven flow fields for transport and selective capture of bacteria Fri, May 16 10:30a…
    ...
    Cilia-driven flow fields for transport and selective capture of bacteria
    Fri, May 16
    10:30am11:00am
    SSR
    Eric Dufresne
    Informal presentation/discussion on droplet ``durotaxis''

    *Aud=Auditorium, SSR=Small Seminar Room, MSR=Main Seminar Room FR=Founders' Room
    ⬆TOP
    (view changes)
    9:23 am

Saturday, May 10

  1. page Challenging Questions edited ... Participants (alphabetic order): Max Bi, Michael Hagan, Ananyo Maitra, Cristina Marchetti, Pa…
    ...
    Participants (alphabetic order):
    Max Bi, Michael Hagan, Ananyo Maitra, Cristina Marchetti, Pawel Romanczuk, Saha Suropriya, Pragya Srivastava, Christoph Weber, Xingbo Yang
    ...
    Romanczuk (Please feel free to
    Main question: What are the different types of self-propelled particle models (SPP-models) ? Where do differences in the microscopic models play a role? What is universal?
    Note: We restrict ourselves here to the discussion of SPP-models with local interactions in space and time (e.g. no pure topological interactions).
    (view changes)
    1:10 pm
  2. page Challenging Questions edited ... Scribe: Pawel Romanczuk (Please free to comment, add new aspects) Main question: What are the…
    ...
    Scribe: Pawel Romanczuk (Please free to comment, add new aspects)
    Main question: What are the different types of self-propelled particle models (SPP-models) ? Where do differences in the microscopic models play a role? What is universal?
    Note: We restrict ourselves here to the discussion of SPP-models with local interactions in space and time (e.g. no pure topological interactions).
    There are many possibilities to classify microscopic models based on e.g.:
    interaction types: "true" physical interactions (attraction, repulsion, hydrodynamics) versus "effective" interactions (e.g. alignment)
    (view changes)
    1:05 pm

Friday, May 9

  1. page Challenging Questions edited ... The other way round it is much more difficult: In general, it is not easy to predict the emerg…
    ...
    The other way round it is much more difficult: In general, it is not easy to predict the emergent phases from some non-trivial interaction rules, and for example interaction rules without explicit alignment may eventually lead also to emergence of long-ranged polar order via more subtle effects.
    If you are interested only in the large-scale behavior of the system (a particual "phase" in a "thermodynamic" sense), a lot of models in the literature are equivalent, so one can go with a simple one (but you have to be aware that your transport coefficients in the hydrodynamic equations may have different dependencies on density)
    ...
    different microscopic modelsmodels, equivalent in the above sense, may be
    Detailed binary collisions studies for various interactions used in SPP-models yield often very inconclusive results, e.g. depending on the collision angle and parameter they may be lead to polar alignment, nematic alignment or have no effect (rel. angle in = rel. angle out) -> Multi-particle effects strongly matter (emergence of local order as a true collective effect)
    Does inertia play a role for the emergent phases? In general, if the relevant time scale of relaxation is much shorter than any time-scales of interest, then it should not matter. However, if one has active particles with an additional degree of freedom with a finite relaxation time (in principle also possible in an active, overdamped system -> "quasi-inertia"), this effects may become important; Possible impact? will depend on the model: either "only" shifting of critical lines, or new instabilities possible.
    (view changes)
    6:24 pm
  2. page Challenging Questions edited ... Participants (alphabetic order): Max Bi, Michael Hagan, Ananyo Maitra, Cristina Marchetti, Pa…
    ...
    Participants (alphabetic order):
    Max Bi, Michael Hagan, Ananyo Maitra, Cristina Marchetti, Pawel Romanczuk, Saha Suropriya, Pragya Srivastava, Christoph Weber, Xingbo Yang
    ...
    Pawel Romanczuk (Please free to comment, add new aspects)
    Main question: What are the different types of self-propelled particle models (SPP-models) ? Where do differences in the microscopic models play a role? What is universal?
    There are many possibilities to classify microscopic models based on e.g.:
    ...
    Based on the symmetries of the "desired" large-scale behavior, one can cook-up a simple microscopic models which are likely to produce it (e.g. polar orientational order -> Vicsek-like model),
    The other way round it is much more difficult: In general, it is not easy to predict the emergent phases from some non-trivial interaction rules, and for example interaction rules without explicit alignment may eventually lead also to emergence of long-ranged polar order via more subtle effects.
    ...
    of models will bein the literature are equivalent, so
    ...
    etc. the behaviorbehaviour of different
    Detailed binary collisions studies for various interactions used in SPP-models yield often very inconclusive results, e.g. depending on the collision angle and parameter they may be lead to polar alignment, nematic alignment or have no effect (rel. angle in = rel. angle out) -> Multi-particle effects strongly matter (emergence of local order as a true collective effect)
    Does inertia play a role for the emergent phases? In general, if the relevant time scale of relaxation is much shorter than any time-scales of interest, then it should not matter. However, if one has active particles with an additional degree of freedom with a finite relaxation time (in principle also possible in an active, overdamped system -> "quasi-inertia"), this effects may become important; Possible impact? will depend on the model: either "only" shifting of critical lines, or new instabilities possible.
    (view changes)
    6:20 pm
  3. page Challenging Questions edited Open Discussion on Self-Propelled Particle Models: Friday, May 9 ... (alphabetic order): M…

    Open Discussion on Self-Propelled Particle Models: Friday, May 9
    ...
    (alphabetic order):
    Max Bi, Michael Hagan, Ananyo Maitra, Cristina Marchetti, Pawel Romanczuk, Saha Suropriya, Pragya Srivastava, Christoph Weber, Xingbo Yang
    Scribe: Pawel Romanczuk
    ...
    Where do the differences in the microscopic models play possibly a role?
    There are many possibilities to classify microscopic models based on e.g.:
    interaction types: "true" physical interactions (attraction, repulsion, hydrodynamics) versus "effective" interactions (e.g. alignment)
    (view changes)
    6:17 pm
  4. page Challenging Questions edited Open Discussion on Self-Propelled Particle Models: Friday, May 9 Participants (alphabetic order…

    Open Discussion on Self-Propelled Particle Models: Friday, May 9
    Participants (alphabetic order):
    Max Bi, Michael Hagan, Ananyo Maitra, Cristina Marchetti, Pawel Romanczuk, Saha Suropriya, Pragya Srivastava, Christoph Weber, Xingbo Yang
    Scribe: Pawel Romanczuk
    Main question: What are the different types of self-propelled particle models (SPP-models) ? Where do the differences play possibly a role? What is universal?
    There are many possibilities to classify microscopic models based on e.g.:
    interaction types: "true" physical interactions (attraction, repulsion, hydrodynamics) versus "effective" interactions (e.g. alignment)
    model formulation: discrete time and/or space (e.g. cellular automata) versus continuous time and space (stoch. differential equations)
    the symmetries of the propulsion mechanism and the microscopic interactions (polar-polar, nematic-nematic, mixed)
    the symmetries of the emergent ordered state(s)
    Models with different microscopic dynamics may yield the same large-scale behavior (eg. orientationally ordered, fluid-like phase), which has universal properties independent on the microscopic model
    The choice of the model depends on the scientific question of interest: e.g large-scale properties of a particular phase, versus (detailed) modelling of a particular experimental system. So first you need to ask the question "What do I want to model and why?".
    Based on the symmetries of the "desired" large-scale behavior, one can cook-up a simple microscopic models which are likely to produce it (e.g. polar orientational order -> Vicsek-like model),
    The other way round it is much more difficult: In general, it is not easy to predict the emergent phases from some non-trivial interaction rules, and for example interaction rules without explicit alignment may eventually lead also to emergence of long-ranged polar order via more subtle effects.
    If you are interested only in the large-scale behavior of the system (a particual "phase" in a "thermodynamic" sense), a lot of models will be equivalent, so one can go with a simple one (but you have to be aware that your transport coefficients in the hydrodynamic equations may have different dependencies on density)
    If you are interested in the emergence of a particular state, transient dynamics and finite systems etc. the behavior of different microscopic models may be very different
    Detailed binary collisions studies for various interactions used in SPP-models yield often very inconclusive results, e.g. depending on the collision angle and parameter they may be lead to polar alignment, nematic alignment or have no effect (rel. angle in = rel. angle out) -> Multi-particle effects strongly matter (emergence of local order as a true collective effect)
    Does inertia play a role for the emergent phases? In general, if the relevant time scale of relaxation is much shorter than any time-scales of interest, then it should not matter. However, if one has active particles with an additional degree of freedom with a finite relaxation time (in principle also possible in an active, overdamped system -> "quasi-inertia"), this effects may become important; Possible impact? will depend on the model: either "only" shifting of critical lines, or new instabilities possible.
    ...

    Discussion Session on Synchronization phenomena in active matter : Friday, April 25
    Discussion leader: Tannie Liverpool, Sriram Ramaswamy
    (view changes)
    6:16 pm
  5. page Talks & Discussions edited ... Jimmy Feng Dorsal closure in the fruit fly: what controls cell oscillation and tissue contrac…
    ...
    Jimmy Feng
    Dorsal closure in the fruit fly: what controls cell oscillation and tissue contraction?
    Fri, May 9
    1:30pm
    FR
    All interested Participants
    Discussion on various agent and particle based models

    Week 10
    Week 17Week 11
    (view changes)
    11:46 am
  6. page Talks & Discussions edited ... *Aud=Auditorium, SSR=Small Seminar Room, MSR=Main Seminar Room FR=Founders' Room ⬆TOP test …
    ...
    *Aud=Auditorium, SSR=Small Seminar Room, MSR=Main Seminar Room FR=Founders' Room
    ⬆TOP
    test
    current week
    (view changes)
    8:37 am
  7. page Talks & Discussions edited ... Hartmut Löwen Self-propelled colloids: from single to collective behaviour Week 10Week 10 …
    ...
    Hartmut Löwen
    Self-propelled colloids: from single to collective behaviour
    Week 10Week 10
    Time
    Place
    ...
    Natsuhiko Yoshinaga
    Spontaneous motion and deformation of a self-propelled droplet
    Week 11Week 11
    Time
    Place
    ...
    Discussion leader: Tannie Liverpool
    come if you are interested
    Week 17Week 17
    Time
    Place
    ...
    Jimmy Feng
    Dorsal closure in the fruit fly: what controls cell oscillation and tissue contraction?
    Week 10
    Week 17Week 11

    Week 19
    Time
    (view changes)
    8:37 am

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