Theory Colloquium

# Towards Bouncing and Genesis Cosmologies

## by Valery Rubakov (INR Moscow)

Wednesday, January 23, 2019 from to (Europe/Berlin)
at DESY Hamburg ( build. 2a, SR2 )
 Description Cosmological Genesis (start from nearly Minkowskian, nearly empty space) and bounce (start with contraction and then transition to expansion) may be viewed as alternatives to inflation. These scenarios are extremely difficult to realize in classical field theory context. The central issue is the necessity to violate of the Null Energy Condition, which leads to instabilities of classical backgrounds in many theories. I report on recent progress in understanding this and other issues, and on successfull attempts to get around them. The latter are based on so called "beyond Horndeski" theories. Material: