  One of the most striking examples for the production of particles out of the
quantum vacuum due to external conditions is cosmological particle creation,
which is caused by the expansion or contraction of the Universe. Already in
1939, Schr\"odinger understood that the cosmic evolution could lead to a mixing
of positive and negative frequencies and that this "would mean production or
annihilation of matter, merely by the expansion". Later this phenomenon was
derived via more modern techniques of quantum field theory in curved
space-times by Parker (who apparently was not aware of Schr\"odinger's work)
and subsequently has been studied in numerous publications. Even though
cosmological particle creation typically occurs on extremely large length
scales, it is one of the very few examples for such fundamental effects where
we actually may have observational evidence: According to the inflationary
model of cosmology, the seeds for the anisotropies in the cosmic microwave
background (CMB) and basically all large scale structures stem from this
effect. In this Chapter, we shall provide a brief discussion of this phenomenon
and sketch a possibility for an experimental realization via an analogue in the
laboratory.
