Speaker
Giovanni Volpe
(Bilkent University, Ankara)
Description
In this talk I will present three projects we have recently
completed:
1) Engineering sensorial delay to control the behaviour of a
group of robots. Ensembles of autonomous agents, such as
swarms of insects, human crowds and groups of robots,
exhibit collective behaviors independent of each agent's
specific motion. In this work, we have shown that time
delays between signal sensing and processing affect the
individual and collective long-term behaviors. Sensorial
delay can therefore be used as a novel parameter to control
these behaviors [1].
2) Experimental measurement of the nonadditivity of critical
Casimir forces. Critical Casimir forces are potentially a
powerful tool to control the self-assembly and complex
behavior of micro- and nanoparticles. In order to fully
exploit their potential, it is crucial to understand whether
and to what extent many-body forces are in action. Despite
having been predicted theoretically, their experimental
demonstration has been lacking. Employing holographic
optical tweezers, we provided the first experimental
demonstration of the nonadditivity of critical Casimir
forces [3].
3) Controlling active matter in disordered potentials. Many
living systems, such as bacterial colonies, exhibit
collective and dynamic behaviors that are sensitive to
changes in environmental conditions. Our results show that a
colloidal active matter system switches between gathering
and dispersal of individuals in response to the roughness of
an attractive potential generated by extended light fields [3].
[1] M Mijalkov, A. McDaniel, J. Wehr & G Volpe, “Engineering
Sensorial Delay to Control Phototaxis and Emergent
Collective Behaviors,” Phys. Rev. X 6, 011008 (2016).
[2] S Paladugu, A Callegari, Y Tuna, L Barth, S Dietrich, A
Gambassi & G Volpe, “Nonadditivity of Critical Casimir
Forces,” Arxiv, 1511.02613 (2015).
[3] E Pince, SKP Velu, A Callegari, P Elahi, S Gigan, G
Volpe & G Volpe, “Disorder-mediated crowd control in an
active matter system,” Nature Commun. 7, in press (2016).
