报告题目：Active Matter: Window to the World in Motion
Department of Physics, Universal Biology Institute, University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, Japan, email@example.com
报告摘要：Active matter is a new window to the world of diverse collective motions. Examples of active matter can be found in artificial self-propelled particles and driven granular matter in soft matter physics, collection of biopolymer, bacterial colonies, and cellular tissues in biological systems. After some reviews, I will give one example of artificial active matter. That is chiral Janus particles moving in a liquid. We demonstrate remote control of chiral Janus particles toward a target by switching between active Brownian motion and rotating motion. Our theoretical analysis revealed the connection between the optimal strategy and “run-and-tumble” mechanism of bacterial chemotaxis. If time allows, I will explain another example of chiral active droplets consists of a chiral liquid crystal exhibiting helical motion is 3D.
Second example will be chosen from biological systems. Self-motility is an important character of living matter. Ranging from filamentous proteins to mobile cells, ensembles of self-propelled particles generate highly non-trivial collective behaviors. In such dynamical collective behaviors, order and disorder can be well characterized by using nematic order parameter and the concept of topological defects in many cases. I will talk about 3D structure formation from 2D sheet of neural stem cells where topological defects become the center for 3D mound formation. This morphological change is reproduced by a simple mathematical model of active matter. Quantitative analysis of the dynamics will be described.