  We study the third quantization of the Friedmann-Robertson-Walker cosmology
with $N$-minimal massless fields. The third quantized Hamiltonian for the WDW
equation in the minisuperspace consists of infinite number of intrinsic
time-dependent, decoupled oscillators. The Hamiltonian has a pair of invariant
operators for each universe with conserved momenta of the fields that play a
role of the annihilation and the creation operators and that construct various
quantum states for the universe. The closed universe exhibits an interesting
feature of transitions from stable states to tachyonic states depending on the
conserved momenta of the fields. In the classical forbidden unstable regime,
the quantum states have googolplex growing position and conjugate momentum
dispersions, which defy any measurements of the position of the universe.
