How to Run Through Walls: Dynamics of Bubble and Soliton Collisions
  It has recently been shown in high resolution numerical simulations that
relativistic collisions of bubbles in the context of a multi-vacua potential
may lead to the creation of bubbles in a new vacuum. In this paper, we show
that scalar fields with only potential interactions behave like free fields
during high-speed collisions; the kick received by them in a collision can be
deduced simply by a linear superposition of the bubble wall profiles. This
process is equivalent to the scattering of solitons in 1+1 dimensions. We
deduce an expression for the field excursion (shortly after a collision), which
is related simply to the field difference between the parent and bubble vacua,
i.e. contrary to expectations, the excursion cannot be made arbitrarily large
by raising the collision energy. There is however a minimum energy threshold
for this excursion to be realized. We verify these predictions using a number
of 3+1 and 1+1 numerical simulations. A rich phenomenology follows from these
collision induced excursions - they provide a new mechanism for scanning the
landscape, they might end/begin inflation, and they might constitute our very
own big bang, leaving behind a potentially observable anisotropy.
