  We present a novel inflationary scenario in theories with low scale (TeV)
quantum gravity, in which the standard model particles are localized on the
branes whereas gravity propagates in the bulk of large extra dimensions. This
inflationary scenario is natural in the brane world picture. In the lowest
energy state, a number of branes sit on top of each other (or at an orientifold
plane), so the vacuum energy cancels out. In the cosmological setting, some of
the branes "start out" relatively displaced in the extra dimensions and the
resulting vacuum energy triggers the exponential growth of the 3 non-compact
dimensions. The number of e-foldings can be very large due to the very weak
brane-brane interaction at large distances. In the effective four-dimensional
field theory, the brane motion is described by a slowly rolling scalar field
with an extremely flat plateau potential. When branes approach each other to a
critical distance, the potential becomes steep and inflation ends rapidly. Then
the branes "collide" and oscillate about the equilibrium point, releasing
energy mostly into radiation on the branes.
