PROGRAM

Joan van der Waals colloquium - John Toner (University of Oregon): 'Swarming in the dirt: Flocking in the presence of quenched disorder'

Date:

Time:

16:00 hrs

Location:

HL106, Huygens building, Leiden

 

 The effect of quenched (frozen) orientational disorder on the collective motion of active particles is analyzed. We find that, as with annealed disorder (Langevin noise), active polar systems are far more robust against quenched disorder than their equilibrium counterparts. In particular, long ranged order (i.e., the existence of a non-zero average velocity <\vec{v}>) persists in the presence of quenched disorder even in spatial dimensions d=2, while it is destroyed even by arbitrarily weak disorder in d \le 4 in equilibrium systems. Furthermore, in d=2, quasi-long-ranged order (i.e., spatial velocity correlations that decay as a power law with distance) occur when quenched disorder is present, in contrast to the short-ranged order that is all that can survive in equilibrium. These predictions are born out by simulations in both 2 and 3 dimensions.

Events

11 - 15 November 2019

Life Sciences with Industry 2019link

21 November 2019

RISE Symposium 2019link