The Fate of Nucleated Black Holes in de Sitter Quantum Gravity

Abstract

The Euclidean Nariai geometry has long been proposed as the instanton describing the nucleation of maximal-mass black holes in de Sitter space. We place this interpretation on firmer footing by showing that, once an observer is included, the gravitational path integral produces the imaginary phase required for a transition rate. As a warmup, we revisit the Hawking-Moss instanton and, as a byproduct, find that scalar fields can enhance black-hole nucleation, suggesting a quantum-gravity bound on scalar potentials with de Sitter solutions. We then study the subsequent semiclassical evolution of the nucleated black hole. We show that the previously claimed "anti-evaporation" channel is unphysical, arising from a quantum state with singular horizons. In a smooth state, the black hole instead undergoes standard thermal Hawking evaporation. We verify explicit agreement with the no-boundary state and argue that this evaporation is not subject to large quantum-gravity corrections. The nucleated black hole thus evaporates completely back to the maximally-entropic empty de Sitter vacuum, making the full process a Boltzmann fluctuation.

68 pages, 3 figures. v2: appendix added on symmetries and the need for an observer in Nariai backgrounds. refs added. v3: updated to match the published JHEP version

References in corpus (19)

• An Investigation of AdS${}_2$ Backreaction and Holography
• An Algebra of Observables for de Sitter Space
• Solvable Models of Quantum Black Holes: A Review on Jackiw-Teitelboim Gravity
• Quantum de Sitter horizon entropy from quasicanonical bulk, edge, sphere and topological string partition functions
• Greybody Factors for Scalar Fields emitted by a Higher-Dimensional Schwarzschild-de-Sitter Black-Hole
• Instabilities and Anti-Evaporation of Reissner-Nordström Black Holes in modified $F(R)$ gravity
• Sphere and disk partition functions in Liouville and in matrix integrals
• Hawking-Moss bounces and vacuum decay rates
• Near-Extremal Limits of de Sitter Black Holes
• Two Wave Functions and dS/CFT on S^1 x S^2
• Islands in Non-Minimal Dilaton Gravity: Exploring Effective Theories for Black Hole Evaporation
• Quantum Cross-section of Near-extremal Black Holes
• Static sphere observers and geodesics in Schwarzschild-de Sitter spacetime
• Quantum Transparency of Near-extremal Black Holes
• Logarithmic corrections to near-extremal entropy of charged de Sitter black holes
• Unveiling horizons in quantum critical collapse
• Quantum Critical Collapse Abhors a Naked Singularity
• The fate of Schwarzschild--de Sitter black holes: nonequilibrium evaporation
• Limits on the Statistical Description of Charged de Sitter Black Holes