Bogoliubov's Integrals of Motion in Quantum Cosmology and Gravity
  Quantum Cosmology and Gravity are formulated here as the primary and secondary quantizations of the energy constraints by analogy with the historical formulation of quantum field theory. New fact is that both the Universe and its matter are created from stable vacuum obtained by the Bogoliubov-type transformation just as it is in the theory of quantum superfluid liquid. Such the Quantum Gravity gives us possibility to explain topical problems of cosmology by the cosmological creation of universes and particles from vacuum. 
V.N. Pervushin and V.A. Zinchuk