A ghost and a naked singularity; facing our demons

Understand

We encounter these demons on the path towards a UV complete QFT of gravity and a horizonless replacement for black holes.

• The fate of the ghost is discussed in the strong coupling version of classically-scale-invariant quadratic gravity.
• Rather than a propagating ghost, the full graviton propagator ends up with a slight acausal behavior.
• We then turn to the 2-2-hole solutions appearing in a classical approximation of the gravity theory.