  We consider the possibility of an oscillating scalar field accounting for
dark matter and dynamically controlling the spontaneous breaking of the
electroweak symmetry through a Higgs-portal coupling. This requires a late
decay of the inflaton field, such that thermal effects do not restore the
electroweak symmetry after reheating, and so inflation is followed by an
inflaton matter-dominated epoch. During inflation, the dark scalar field
acquires a large expectation value due to a negative non-minimal coupling to
curvature, thus stabilizing the Higgs field by holding it at the origin. After
inflation, the dark scalar oscillates in a quartic potential, behaving as dark
radiation, and only when its amplitude drops below a critical value does the
Higgs field acquire a non-zero vacuum expectation value. The dark scalar then
becomes massive and starts behaving as cold dark matter until the present day.
We further show that consistent scenarios require dark scalar masses in the few
GeV range, which may be probed with future collider experiments.
