Sean Gryb: Hidden symmetries and the role of scale in physics

While measurement outcomes are necessarily recorded in terms of dimensionless numbers (e.g., the length ratio between an object and some probe), scientific theories are almost exclusively formulated in terms of dimension-full quantities (e.g., meters). Such usage of fixed scales seems justifiable for theories that make reference to external reference structures. However, for cosmological theories such as general relativity, a more careful scrutiny of the role played by scale is required. We will study...(continue reading...)