Multi-Stream Inflation: Bifurcations and Recombinations in the
  Multiverse
  In this Letter, we briefly review the multi-stream inflation scenario, and
discuss its implications in the string theory landscape and the inflationary
multiverse. In multi-stream inflation, the inflation trajectory encounters
bifurcations. If these bifurcations are in the observable stage of inflation,
then interesting observational effects can take place, such as domain fences,
non-Gaussianities, features and asymmetries in the CMB. On the other hand, if
the bifurcation takes place in the eternal stage of inflation, it provides an
alternative creation mechanism of bubbles universes in eternal inflation, as
well as a mechanism to locally terminate eternal inflation, which reduces the
measure of eternal inflation.
