  The linear Stark effect shows that the first excited state of hydrogen atom
has large permanent electric dipole moment (EDM), d(H)=3eao (ao is Bohr
radius). Using special capacitors our experiments discovered that the ground
state K, Rb or Cs atom is polar atom with a large EDM of the order of eao as
hydrogen atom of excited state. Their capacitance(C) at different voltage (V)
was measured. The C-V curve shows that the saturation polarization of K, Rb or
Cs vapor has be observed when the field E more than ten to the fifth power V/m.
When the saturation polarization appeared, nearly all K, Rb or Cs atoms(more
than 98 percent) turned toward the direction of the field, and C is
approximately equal to Co (Co is vacuum capacitance) or their dielectric
constant is nearly the same as vacuum! K, Rb or Cs vapor just exist in the
lowest energy state, so we see the vacuum state containing a large number of
atoms! Due to the saturation polarization of hydrogen vapor of excited state is
easily appears, we conjecture that a vacuum state containing a large number of
hydrogen atom of excited state may exist at early Universe when the absolute
temperature T is approximately equal to ten to the fifth power K.
