Speaker
Description
Quantum gravity corrections at the classical level are typically expected to be negligible. In this talk, I will present a mechanism by which even parametrically small corrections to the Schwarzschild solution, Planck-suppressed at asymptotic scales, become dominant in the near-horizon region. By analyzing linear perturbations around the Schwarzschild background, we find that higher-derivative terms, which introduce additional propagating degrees of freedom, are exponentially amplified as one approaches the horizon. Once the couplings controlling these terms are switched on, however small, their contribution grows and qualitatively modifies the near-horizon geometry: the classical event horizon is removed and replaced either by a naked singularity or by a wormhole-like structure. We illustrate this mechanism in several extensions of general relativity, including quadratic gravity, perturbative counterterms, and Einsteinian cubic gravity, and discuss the implications for constraining the Wilsonian effective action of gravity with observational data.