Gauss-Bonnet braneworld redux: A novel scenario for the bouncing
  universe
  We propose a new scenario for the bouncing universe in a simple
five-dimensional braneworld model in the framework of Einstein-Gauss-Bonnet
gravity, which works even with ordinary matter on the brane. In this scenario,
the so-called branch singularity located at a finite physical radius in the
bulk spacetime plays an essential role. We show that a three-brane moving in
the bulk may reach and pass through it in spite of the fact that it is a
curvature singularity. The bulk spacetime is extended beyond the branch
singularity in the C^0 sense and then the branch singularity is identified as a
massive thin shell. From the bulk point of view, this process is the collision
of the three-brane with the shell of branch singularity. From the point of view
on the brane, this process is a sudden transition from the collapsing phase to
the expanding phase of the universe. The present result opens a completely new
possibility to achieve the bouncing brane universe as a higher-curvature
effect.
