Week 18.05.2026 – 24.05.2026

Active matter consists of systems whose constituents continuously consume energy to drive motion far from equilibrium, giving rise to a rich variety of emergent collective behaviours. In this talk, I will discuss two active systems, one synthetic and one biological, that exhibit striking dynamical phenomena. I will first focus on superwalking droplets, where self-propelled droplets coupled to long-lived surface waves display memory-driven dynamics that can be captured by a Lorenz-like dynamical system, leading to increasingly complex behaviour as memory is increased. I will then discuss recent work on the quantitative modelling of collective cell migration during anterior-posterior patterning in the mouse embryo, where intermittent start-stop motion emerges from the rheology and stress relaxation dynamics of the surrounding tissue.

I will discuss old and new results about the distribution of zeros of modular forms, and relation to Quantum Unique Ergodicity. It is known that a modular form of weight k has about k/12 zeros in the fundamental domain . A classical question in the analytic theory of modular forms is “can we locate the zeros of a distinguished family of modular forms?”. In 1970, F. Rankin and Swinnerton-Dyer proved that the zeros of the Eisenstein series all lie on the circular part of the boundary of the fundamental domain. In the beginning of this century, I discovered that for cuspidal Hecke eigenforms, the picture is very different - the zeros are not localized, and in fact become uniformly distributed in the fundamental domain. Very recently, we have investigated other families of modular forms, such as the Miller basis (ZR 2024, Roei Raveh 2025, Adi Zilka 2026), Poincare series (RA Rankin 1982, Noam Kimmel 2025) and theta functions (Roei Raveh 2026), finding a variety of possible distributions of the zeroes.