Seminar of Research Training Group
Catching ghosts -- from unitarity to asymptotic safety
Tuesday June 13, 2017 16:15:00 CEST
Tuesday June 13, 2017 17:45:00 CEST
Chris Ripken (Radboud University Nijmegen)
Higher derivative theories arise naturally in the context of effective quantum field theories. However, it is well-known that these theories generally are non-unitary.
The purpose of this talk is two-fold. First, I will show why higher derivative theories are unitarity violating by discussing its Euclidean analogue, which is called Reflection Positivity.
Secondly, we will consider a way of dealing with higher-derivative theories by means of the Renomalization Group. A requirement similar to Asymptotic Safety may be imposed on the infrared side of the RG trajectory to provide a unitary EFT.