Prediction of the tensor-to-scalar ratio in primordial cosmology from quantum gravity with purely virtual particle

I discuss the quantization of purely virtual particles in quantum gravity and its applications to primordial cosmology. The inflation mechanism is unique and coincides with the Starobinsky one. However, the Weyl squared term included in the action, which must be understood as purely virtual, changes the final predictions. In particular, the tensor-to-scalar ratio r lies within the range $0.0004 < r < 0.0035$. Tilts and higher-order corrections can be calculated by viewing inflation as a certain RG flow. The spectra are understood as correlation functions that obey Callan-Symanzik equations. They can be expressed as expansions in powers of a running "fine structure" constant of inflation.