The hidden assumption
At the heart of both problems sits the same unexamined premise. The standard model of black hole accretion treats the infalling plasma as a single fluid - electrons and ions moving together in perfect lockstep, always. This assumption is built so deeply into the mathematical framework that it rarely appears explicitly. It is simply taken as given.
In most environments, it is a reasonable approximation. But in the narrow polar funnels above a spinning, radiation-bright black hole - exactly the environment most relevant to both problems - it is wrong. Electrons and ions are profoundly different particles with profoundly different responses to the forces acting on them. When the coupling between them is given finite, physical values rather than an idealized infinity, everything changes.
What Coulomb Shearing is
The Eddington limit describes the point at which outward radiation pressure on electrons balances inward gravity. It is a correct and well-established result. The problem is the step that follows: the assumption that because radiation stops electrons, it also stops ions - because the two are coupled perfectly and instantaneously.
Coulomb Shearing is what happens when that coupling fails. In the polar channels of a rapidly spinning black hole, radiation drives electrons outward with enormous force while the much heavier ions barely respond. The electromagnetic coupling between them - real, but finite - cannot resynchronize the species fast enough. Their separation grows beyond the plasma's natural screening scale. The bond breaks. The two particle populations decouple and follow their own physics.
Electrons stream outward into the jet. Ions fall inward freely, no longer subject to the electron-radiation interaction that enforces the growth ceiling. The result, simultaneously, is an explanation for jet structure and composition, and an explanation for why black holes grow far faster than the classical model permits.
What it explains
With ions accreting freely once coupling fails, growth rates exceed the classical Eddington ceiling in a quantifiable, physically grounded way - resolving the mass paradox that has challenged cosmology for decades. The electron-rich spine and ion-dominated sheath of relativistic jets are a direct, computed consequence of the same species separation - not an assumed geometry, but a natural outcome.
Specific rotation measure patterns, depolarization signatures, and jet stratification profiles are predicted quantitatively for real systems - including M87* - and can be confirmed or refuted with existing telescopes.
How it is tested
The framework is evaluated against real astrophysical systems using a strict, pre-committed protocol. Observational inputs are fixed before calculations run. No parameters are adjusted after the fact.
"The paper reframes black hole growth as a species-resolved transport problem and establishes Coulomb Shearing as a decisive mechanism that either succeeds quantitatively in the relevant regimes or fails transparently when confronted with data."
- Coulomb Shearing: Electron-Ion Coulomb Shearing as a Dominant Growth Mechanism in Eddington-Limited Regimes, Deadman (2026). DOI: 10.5281/zenodo.19671941
Why it matters
Black hole growth and relativistic jets are not peripheral topics in astrophysics. They sit at the center of our understanding of how galaxies form, how the early universe evolved, and how the most energetic phenomena in the cosmos work. Explanations for either problem, separately, would represent a major advance. A single physical mechanism that accounts for both - derived from first principles, applied to real systems, and designed to be tested - is of a different order entirely.
The physics was always there, written into the difference between an electron and an ion. It just required treating them as the distinct particles they are.