Exact Results in Quantum Theory

The destructive interference of the neighboring field configurations with infinite classical action in the gravitational path integral approach serves as a dynamical mechanism resolving the black hole singularity problem. It also provides an isotropic and homogeneous early universe without the need for inflation. The path integral approach yields a powerful framework in the quantum theory. It emphasizes Lorentz covariance and allows for the description of non- perturbative phenomena. In the path integral, one sums over all possible configurations of a field(s) weighted by exp(iS[\Phi])], where S[\Phi] is the classical action of the theory. In the Minkowski path integral, the classical action approaching infinity causes fast oscillations in the exponential weight and hence the destructive interference of the neighboring field configurations. Such configurations do not contribute to the physical quantities. Furthermore, in Wick rotated path integral is weighted by exp(-S[\Phi]), and the field configuratioon which the action is infinite do not contribute at all. This provides theoretical motivation for the Finite Action Principle, saying that an action of the universe should be finite. This principle has a significant impact on the nature of quantum gravity and the cosmological evolution, once the higher-curvature terms are included. In the framework of Horava-Lifshitz gravity, field configurations with finite classical action describe a universe with a homogeneous and isotropic beginning, without black hole singularities and ghost particles. Zoom: Meeting ID: 861 0663 2208 Passcode: 673023