Infinite distance limits in families of quantum theories are observed to enjoy a number of seemingly universal properties: they have "logarithmic" metric singularities, are always associated with weak-coupling limits, and---in quantum gravitational theories---are tied to the appearance of a tower of exponentially light fields. The goal of this talk is to explain why these features are universal. By using information-theoretic tools, I will explain how the first two properties are consequences of unitarity: it dictates that, in these limits, observables must factorize and the metric must have a logarithmic singularity. I will also explain why these limits necessarily have such dramatic behavior in quantum gravitational theories. Since gravity universally couples to stress energy, it presents a fundamental obstacle to factorization and must decouple in any consistent factorization limit. I will explain how this perspective provides a bottom-up motivation for the Swampland Distance Conjecture and points towards ways around it.
14:00 - 16:00 (Europe/Zurich)
Infinite Distance Limits and Factorization
4/3-006 at CERN