Black universes with trapped ghosts
  A black universe is a nonsingular black hole where, beyond the horizon, there
is an expanding, asymptotically isotropic universe. Such models have been
previously found as solutions of general relativity with a phantom scalar field
as a source of gravity and, without phantoms, in a brane world of RS2 type.
Here we construct examples of static, spherically symmetric black-universe
solutions in general relativity with a minimally coupled scalar field \phi
whose kinetic energy is negative in a restricted strong-field region of
space-time and positive outside it. Thus in such configurations a "ghost" is
trapped in a small part of space, which may in principle explain why no ghosts
are observed under usual conditions.
