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Abstract |
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, and the extent to which,
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, there must be observables that 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. |
