25 research outputs found
Curing black hole singularities with local scale invariance
We show that Weyl-invariant dilaton gravity provides a description of black
holes without classical spacetime singularities. Singularities appear due to
ill-behaviour of gauge fixing conditions, one example being the gauge in which
theory is classically equivalent to standard General Relativity. The main
conclusions of our analysis are: (1) singularities signal a phase transition
from broken to unbroken phase of Weyl symmetry, (2) instead of a singularity
there is a "baby-universe" or a white hole inside a black hole, (3) in the baby
universe scenario there is a critical mass after which reducing mass makes
black hole larger as viewed by outside observers, (4) if a black hole could be
connected with white hole through the "singularity", this would require
breakdown of (classical) geometric description, (5) the singularity of
Schwarzschild BH solution is non-generic and so it is dangerous to rely on it
in deriving general results. Our results may have important consequences for
resolving issues related to information-loss puzzle. The theory we use is
basically a completion of General Relativity, containing neither additional
physical excitations nor higher-derivative terms, but requires physical scalar
field such as Higgs field of Standard Model. Though quantum effects are still
crucial and may change the proposed classical picture, a position of building
quantum theory around essentially regular classical solutions normally provides
a much better starting point.Comment: 13 pages, 2 figures, v2: Improved explanations, restoration of Weyl
symmetry emphasized. References added. v3: Misprints corrected, improved
explanations, one new figure. References added. v4: improved explanations.
Discussion on regularity of observables added. v5: improved presentation,
additional examples added. Main results and conclusions unchanged. Matches
published versio