Regular multi-horizon Lee-Wick black holes

TL;DR

This paper explores the complex structure of static spherically symmetric Lee-Wick black holes, revealing oscillations, multiple horizons, and unique thermodynamic behaviors across the full parameter space.

Contribution

It provides a comprehensive analysis of Lee-Wick black holes considering the full parameter space, uncovering oscillatory features and thermodynamic properties not previously studied.

Findings

Oscillations in the metric depending on the ratio b/a

Multiple horizons and mass gaps in solutions

Existence of cold black holes with zero Hawking temperature

Abstract

In this paper we carry out a detailed analysis of the static spherically symmetric solutions of a sixth-derivative Lee-Wick gravity model in the effective delta source approximation. Previous studies of these solutions have only considered the particular case in which the real and the imaginary part of the Lee-Wick mass $\mu=a +i b$ are equal. However, as we show here, the solutions exhibit an interesting structure when the full parameter space is considered, owing to the oscillations of the metric that depend on the ratio $b/a$. Such oscillations can generate a rich structure of horizons, a sequence of mass gaps and the existence of multiple regimes for black hole sizes (horizon position gaps). In what concerns the thermodynamics of these objects, the oscillation of the Hawking temperature determines the presence of multiple mass scales for the remnants of the evaporation process and may permit the existence of cold black holes with zero Hawking temperature $T$ and quasi-stable intermediate configurations with $T \approx 0$ and a long evaporation lifetime. For the sake of generality, we consider two families of solutions, one with a trivial shift function and the other with a non-trivial one (dirty black hole). The latter solution has the advantage of reproducing the modified Newtonian-limit metric of Lee-Wick gravity for small and large values of $r$.