Quantum mechanics of the early universe

Quantum tunneling of the universe from open-quotes nothingclose quotes into a de Sitter vacuum, interpreted as the birth of the universe from a vacuum, is considered. Vilenkin's results are generalized by allowing for strings, domain walls, and various kinds of compressed matter that contribute to the potential through which the tunneling occurs. The energy spectrum of the universe in the quantum pre-de Sitter stage, the coefficient of passage through the potential barrier, which describes the probability of birth of the universe, and the conditions of applicability of the quasi-classical approximation in the calculation of these quantities are found