Speaker
Dr
Frank KOENNIG
(Institute for Theoretical Physics, University of Heidelberg)
Description
I will discuss the constraints for the absence of gradient
instabilities in the scalar sector and the Higuchi ghost.
These will
show that all infinite branches suffer from the Higuchi
ghost at all
times and provide a relation between ghost-like helicity-0 and
helicity-2 dofs. Furthermore, I will briefly discuss "exotic"
branches, like bouncings or asymptotic static universes, and
comment
on one promising way to solve the gradient instability
problem in
finite branches.
