报告题目：Living and Soft Matter: From Non-Equilibrium Phase Separation to Anti-Infection Catheters
报告人：周廷弢博士 美国加州理工学院
报告时间：2026年7月25日下午2:00
报告地点：物理科技楼409室
报告摘要：Living matter, such as microbial colonies, animal flocks, or human populations, are intrinsically out of equilibrium. Understanding the fundamental behaviors of these systems not only addresses intriguing theoretical challenges in non-equilibrium statistical physics but also enables impactful applications in biomedical and materials sciences.
In the first part of this talk, I will discuss our recent work resolving a central open question in active matter physics: does motility-induced phase separation (MIPS)—robust in “dry” active models—survive in realistic, fluid (“wet”) environments where long-ranged, many-body hydrodynamic interactions (HI) operate? Using theory and Active Fast Stokesian Dynamics simulations of ‘squirmers’, we reveal that collision-induced pusher dipoles, which is a generic many-body HI effect that arises for any type of microswimmers, destroy MIPS across parameter space. These dipoles destroy MIPS by (1) enhancing the rotational diffusion of the swimmers and (2) generating advective flows that sweep swimmers away from dense clusters. These results transform how the community interprets dense phases in wet active systems and offer a clear, testable prescription for designing them.
In the second part of this talk, I will present a geometric design for anti-infection catheters. Urinary catheters cause lots of infections in hospitalized patients and cost about 30 million US dollars annually. By understanding microbial transport in channels, specifically how bacteria swim upstream due to flow-induced reorientation, we propose a novel catheter interior design that reduces bacterial contamination by 100-fold, potentially preventing urinary tract infections associated with indwelling catheters.
报告人简介：Dr. (Edmond) Tingtao Zhou received his B.S. in Physics from Peking University in China, where he worked on statistical physics of star formation. He then pursued his Ph.D. in Physics at MIT, where his thesis focused on phase transition induced deformations in porous colloidal media, such as cement or batteries. Currently, he is a Drinkward Postdoc Fellow at California Institute of Technology, where he combines statistical physics and fluid mechanics to study the fundamentals of living matter and its applications in biomedical and responsive materials.
