Active Matter Influence on Coffee Rings preprint in arXiv

Active Matter Alters the Growth Dynamics of Coffee Rings

Active Matter Alters the Growth Dynamics of Coffee Rings
Tuğba Andaç, Pascal Weigmann, Sabareesh K. P. Velu, Erçağ Pinçe, Agnese Callegari, Giorgio Volpe & Giovanni Volpe
arXiv: 1803.02619

We experimentally demonstrate the light-controlled assembly of active colloidal molecules from a suspension of two species of passive microspheres.When light is shone on the sample, the active molecules form and acquire motility through non-reciprocal interactions between their passive components. As their size grows, they feature a complex array of behaviors, becoming propellers, spinners and rotators. Their shape and functionality can be tuned by applying periodic illumination. We also provide a theoretical model allowing to predict the complete table of emerging active molecules and their properties in quantitative agreement with the experiments.

Microscopic Crowd Control published in Nature Commun.

Disorder-mediated crowd control in an active matter system

Disorder-mediated crowd control in an active matter system
Erçağ Pinçe, Sabareesh K. P. Velu, Agnese Callegari, Parviz Elahi, Sylvain Gigan, Giovanni Volpe & Giorgio Volpe
Nature Communications 7, 10907 (2016)
DOI: 10.1038/ncomms10907

Living active matter systems such as bacterial colonies, schools of fish and human crowds, display a wealth of emerging collective and dynamic behaviours as a result of far-from- equilibrium interactions. The dynamics of these systems are better understood and controlled considering their interaction with the environment, which for realistic systems is often highly heterogeneous and disordered. Here, we demonstrate that the presence of spatial disorder can alter the long-term dynamics in a colloidal active matter system, making it switch between gathering and dispersal of individuals. At equilibrium, colloidal particles always gather at the bottom of any attractive potential; however, under non-equilibrium driving forces in a bacterial bath, the colloids disperse if disorder is added to the potential. The depth of the local roughness in the environment regulates the transition between gathering and dispersal of individuals in the active matter system, thus inspiring novel routes for controlling emerging behaviours far from equilibrium.

 

Featured in:
Understanding the dynamics of crowd behavior”, Phys.com
Understanding the dynamics of crowd behavior”, ScienceDaily.com
Physics Explains Group Dynamics: When There’s Chaos, Individuals Disperse”, Medical Daily
Ученые выяснили, как меняющаяся окружающая среда влияет на движение толпы”, Gazeta.ru
Understanding the dynamics of crowd behaviour”, Nano
Understanding the dynamics of crowd behaviour”, Noodls
Understanding the dynamics of crowd behavior”, EurekAlert!
Understanding the dynamics of crowd behavior”, Informs
Understanding the dynamics of crowd behavior”, Nanowerk