# Infinite Distance Limits and Factorization

- Institution: CERN
- Department: TH String Theory Seminar
- Speaker: John Stout
- Year: 2023
- Language: English
- Source: [CERN](https://videos.cern.ch/record/3001047)
- Licence: [CERN](http://copyright.web.cern.ch)
- Who can watch: Teens profiles and older (sources give no ratings; placed by Invisible Network from the source's own words)

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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## Lectures

1. [Infinite Distance Limits and Factorization](https://invisiblenetwork.ai/learn/cern/3001047/2f89be28c7f9), 1 h 14 min (CERN's player)