Infinite Distance Limits and Factorization

by John Stout (Harvard University)

Tuesday 21 Mar 2023, 14:00 → 16:00 Europe/Zurich

4/3-006 - TH Conference Room (CERN)

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.

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