  The decoherence of quantum fluctuations into classical perturbations during
inflation is discussed. A simple quantum mechanical argument, using a spatial
particle wavefunction rather than a field description, shows that observable
correlations from inflation must have a discrete spectrum, since they originate
and freeze into the metric within a compact region. The number of discrete
modes is estimated using a holographic bound on the number of degrees of
freedom. The discreteness may be detectable in some models; for example, if
there is a fundamental universal frequency spectrum, the inflationary
gravitational wave background may be resolvable into discrete emission lines.
