Hamiltonian Approach to Cosmological Perturbations in General Relativity

Abstract

The Hamiltonian approach to General Relativity is developed similarly to the Wheeler-DeWitt Hamiltonian cosmology, where the cosmological scale factor is treated as a time-like dynamic variable and its canonical momentum is considered as an evolution generator in the field space of events with the postulate about a physical vacuum as a state with the minimal eigenvalue of this generator.The cosmological scale factor is extracted from the Hamiltonian General Relativity without double counting of the spatial metric determinant in contrast to the standard cosmological perturbation theory. The Friedmann-like equations in the exact theory are derived. A new version of cosmological perturbation theory keeps the form of the Newton interactions in an early Universe. We show how the considered Hamiltonian approach to GR can solve the topical problems of modern cosmology and quantum theory of gravitation.