Essential Quantum Einstein Gravity

The non-perturbative renormalisation of quantum gravity is investigated allowing for the metric to be reparameterised along RG flow, such that only essential couplings constants are renormalised. This allows us identify a universality class which guaranteed unitary, since physical degrees freedom those general relativity without matter and with vanishing cosmological constant. Considering all diffeomorphism invariant operators up four derivatives, Newton’s constant at Gaussian infrared fixed point associated linearised Einstein–Hilbert action. other inessential can then values they take flow within this class. In ultraviolet, corresponding beta function vanishes interacting Reuter point. properties stable between approximation including derivative terms in equation. Our results suggest relevant coupling Therefore, we conjecture Einstein gravity, ultraviolet completion Einstein’s theory asymptotic safety scenario, has no free parameters absence particular predicts