Black holes might not vanish after all.
A theoretical study says they could stop evaporating at the last moment and leave behind tiny, stable remnants that keep all the information they once held. The same model also points to a possible geometric origin for the mass of elementary particles.
The work, led by Richard Pinčák and published in General Relativity and Gravitation, tackles the black hole information paradox, a problem that traces back to Stephen Hawking’s work in the 1970s.
Hawking’s semi-classical calculations showed that black holes emit faint radiation, slowly lose energy, shrink and eventually disappear. That created a conflict with quantum mechanics, which says information cannot be destroyed. If a black hole evaporates completely, information about the matter that fell into it appears to vanish too.
The new study proposes a different ending. The researchers say the answer may lie in a higher-dimensional model based on Einstein-Cartan theory in 7 dimensions on a G2-manifold with torsion.
Unlike general relativity, which allows spacetime to curve, Einstein-Cartan theory also allows it to twist. The study says this spacetime torsion becomes especially important at the extreme densities linked to the Planck scale, where it creates a repulsive force against gravitational collapse.
According to the researchers, that repulsive effect can halt the final stage of Hawking evaporation. Instead of disappearing completely, a black hole would leave a stable remnant with a predicted mass of about 9 x 10^-41 kilograms.
The study says the remnant would act as a long-term information store. In the model, information is kept in a spectrum of “quasi-normal modes” tied to the remnant’s structure. More specifically, quantum information is encoded in long-lived “vibrations” of the torsion field inside the remnant’s geometry.
The researchers calculated that a remnant left by a black hole with the mass of the Sun could store about 1.515 x 10^77 qubits of information. They say that is enough to preserve the information needed to resolve the paradox.
The paper also links the idea to particle physics. The researchers argue that reducing the geometry from 7 dimensions to the 4 dimensions of observed spacetime naturally produces the electroweak scale, about 246 GeV.
The study says the vacuum expectation value of the torsion field is dynamically identified with that electroweak scale, which is closely tied to the Higgs field and the masses of elementary particles. In the model, the same geometric mechanism that stops complete black hole evaporation and preserves quantum information could also explain the mass hierarchy problem.
The paper says particles associated with the extra dimensions, called Kaluza-Klein excitations, would have masses of roughly 8.6 x 10^15 GeV. That is about seven orders of magnitude beyond the reach of the Large Hadron Collider.
Still, the authors say the framework makes specific predictions that could be tested through astronomical observations. One possibility is the stable remnants themselves, which the study says could contribute to dark matter.
The model also predicts specific features in the way information is encoded in the remnants’ “vibrations,” or quasi-normal modes. The study says traces of the proposed 7-dimensional geometry could also be preserved in the cosmic microwave background or in primordial gravitational waves.
The paper is “Geometric origin of a stable black hole remnant from torsion in G2-manifold geometry,” by Richard Pinčák, Alexander Pigazzini, Michal Pudlák and Erik Bartoš.
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