Скачать или смотреть Terry Tomboulis - Nonlocal vertices, UV “opaqueness” and causality

QGRAV2021
International Workshop on Quantum Gravity, Higher Derivatives & Nonlocality
8th to 12th March 2021
https://www.qgrav2021.com/​
https://www.qgrav2021.inpcs.net/

Abstract: There are several physical motivations for considering nonlocality of interactions. A basic
one is the well-known argument, discussed over several decades, that, in the presence of
gravitational interactions, there must be a fundamental limitation on the resolution achievable by
any conceivable experiment probing scales of the order of some fundamental (Planck order) length.
We will present some recent work on how one may implement this picture in field theory within a
multi-scale analysis framework, which allows sequestering of the extreme UV, so that interactions
become `soft' and coarse over such scales, thus preventing finer resolution. This naturally results in
nonlocal vertices of particular types, with Feynman rules resembling those of string field theory. A
central question that will be discussed is how local gauge symmetries can be accommodated within
such a multi-scale framework. For these interactions, a rigorous asymptotic analysis of potential
acausal effects in scattering amplitudes can be given bounding them by exponential suppression,
thus essentially confining them to Planck scale effects.