SPECIAL PHYSICS COLLOQUIUM | Paul Dirac Collegiate Professorship in Physics Inaugural Lecture Epidemics, Erdos Numbers, and the Internet: The Physics of Networks

There are networks in almost every part of our lives. Some of them are familiar and obvious: the Internet, the power grid, the road network. Others are less obvious but just as important. The patterns of friendships or acquaintances between people form a social network; the species in an ecosystem join together to form a food web; the workings of the body's cells are dictated by a metabolic network of chemical reactions. As large-scale data on these networks and others have become available in the last few years, a new science of networks has grown up, drawing on ideas from physics, math, computer science, biology, and other fields to shed light on systems ranging from bacteria to the whole of human society. This lecture will describe some new discoveries regarding networks, how those discoveries were made, and what they can tell us about the way the world works.