  In a primordial universe pre(post)-inflationary era , there could be phases
of early universe made of cold gas baryons, radiation and early post
inflationary cosmological constant. I showed that in the baryonic epoch, the
quantum vacuum is unique. By using the standard quantization scheme for a
massive minimally coupled scalar field with maximal conformal symmetry in the
classical spacetime, I demonstrated that the scalar modes had an effective mass
$m_{eff}^2\approx 0$ (or $m_{eff}^2\approx constant$). This argument validated
when the conformal time $\eta$ kept so close to the inflation ending time
$\eta=\eta_c$. The energy density of the baryonic matter diverged at the
inflation border and vanishes at the late time future. Furthermore I argued
that at very early accelerating epoch when the radiation was the dominant part
in the close competition with the early time cosmological constant, fine tuned
mass of the scalar field $m\propto \sqrt{\Lambda}$ also provided a unique
quantum vacuum. The reason is that the effective mass eventually is vanished. A
remarkable observation was that all the other possible vacuum states "squeezed"
eternally.
