Emergent Universe from Noncommutative Spacetime
ABSTRACT The Big Bang, which was the birth of our Universe, happened at the Planck epoch. It was not an event that developed in a pre-existing space-time. Rather, it was a cosmological event simultaneously generating space-time as well as all other matter fields. Therefore, in order to describe the origin of our Universe, it is necessary to have a background-independent theory for quantum gravity in which no space-time structure is a priori assumed, but is defined from the theory. The emergent gravity based on noncommutative gauge theory provides such a background-independent formulation of quantum gravity, and the emergent space-time leads to a novel picture of the dynamical origin of space-time. We address some issues about the origin of our Universe and discuss the implications to cosmology of the emergent gravity.