  I propose a new mechanism to account for the observed tiny but finite dark
energy in terms of a non-Abelian Higgs theory, which has infinitely many
perturbative vacua characterized by a winding number, in the framework of
inflationary cosmology. Inflation homogenizes field configuration and
practically realizes a perturbative vacuum with vanishing winding number, which
is expressed by a superposition of eigenstates of the Hamiltonian with
different vacuum energy density. As a result, we naturally find a nonvanishing
vacuum energy density with fairly large probability, under the assumption that
the cosmological constant vanishes in some vacuum state. Since the predicted
magnitude of dark energy is exponentially suppressed by the instanton action,
we can fit observation without introducing any tiny parameters.
