Asymptotic safety in Lorentzian quantum gravity

A recently introduced functional renormalization group (RG) provides a new tool to explore nonperturbative and covariant RG flows in Lorentzian spacetimes. We apply it for the first time to investigate the ultraviolet limit of quantum gravity. While the RG flow is state dependent, it is possible to evaluate state- and background-independent contributions to the flow. Taking into account only these universal terms, the RG flow exhibits a nontrivial fixed point in the Einstein-Hilbert truncation, providing a mechanism for asymptotic safety in Lorentzian quantum gravity.