  Vacuum properties of quantum chromodynamics in strong magnetic and finite
electric fields are investigated. We show that when a uniform electric field is
instantaneously applied in the parallel direction to a strong magnetic field,
it induces temporal oscillation of the chiral and pion condensates. This is a
temporal analog to the chiral spiral. The oscillation originates with the
propagation of the collective mode, which is protected by the axial anomaly and
thus nondissipative.
