Gravity seminar - Thomas van Riet Seminar

Abstract: In the late 80's and 90's Euclidean wormholes were believed to be
relevant saddle points contributing to the Euclidean path integral. When
they do so, they come with several puzzles regarding unitarity, locality
etc. In recent years Euclidean wormholes have shown to be important in
understanding low-dimensional models of quantum gravity. It is unclear
whether the same is true in four spacetime dimensions (or higher). In
this talk I will explain that Coleman's Euclidean wormholes come about
in presence of axion fields, how holography seems to indicate they are
somehow spurious objects and how explicit computations indeed seem to
point to several perturbative instabilities. The talk is intended for a
broad audience and is hopefully pedagogical.

 

Talk slides