Quantum cosmology: a review
  In quantum cosmology, one applies quantum physics to the whole universe.
While no unique version and no completely well-defined theory is available yet,
the framework gives rise to interesting conceptual, mathematical and physical
questions. This review presents quantum cosmology in a new picture that tries
to incorporate the importance of inhomogeneity: De-emphasizing the traditional
minisuperspace view, the dynamics is rather formulated in terms of the
interplay of many interacting "microscopic" degrees of freedom that describe
the space-time geometry. There is thus a close relationship with
more-established systems in condensed-matter and particle physics even while
the large set of space-time symmetries (general covariance) requires some
adaptations and new developments. These extensions of standard methods are
needed both at the fundamental level and at the stage of evaluating the theory
by effective descriptions.
