A colloquium by Prof. Joern Davidsen (University of Calgary) presented by the Department of Physics & Astronomy and the Canadian Association of Physicists (CAP). This colloquium is part of the 2026 CAP Lecture tour.
Date/Time: Wednesday March 19, 1:30 - 2:45 p.m.
Location: SA8002 (BMO Auditorium)
Title: Physics of Complex Systems: Criticality in Nature
Abstract:
Physical, geophysical, chemical, living and human-made systems often show behaviours that cannot be understood by studying their building blocks or constituents to ever finer detail but that are emergent. The concept of emergence can be summarized by the statement that there exists an entity (e.g. an organism) which is more than the sum of its parts. This is often used as the defining property of a complex system. Hallmarks of criticality, such as power-laws and self-similarity typical for order-disorder phase transitions in statistical physics, have been found in many complex systems in nature ranging from fault networks to biological networks. In particular, biological neuronal systems are often thought to be organized in such a way that they optimize their information processing and storage capabilities. This is supported by studies, which have indicated that neuronal networks in vivo and in vitro can self-organize to a critical state. In this talk, I will discuss what complex systems are, why they are interesting and how we try to describe and understand their emergent characteristics such as criticality including the self-organization processes leading to them. The focus will be on information processing and memory consolidation in neuronal systems and the spreading of zoonotic diseases as well as the failure of rock samples and fluid-induced seismicity, such as encountered in enhanced geothermal systems and hydraulic fracturing.
Contact:
Heliudson Bernardo | heliudson.bernardo@uleth.ca
