High-energy interactions of charged black holes in full general relativity. II. Near-extremal merger remnants and universality with the irreducible mass
Bibliographic record
Abstract
In a preceding paper [M A. M. Smith, V. Paschalidis, and G. Bozzola, High-energy interactions of charged black holes in full general relativity. I. Zoom-whirl orbits and universality with the irreducible mass, Phys. Rev. D 111, 104031 (2025)], we initiated a study of high-energy interactions of charged binary black holes near the scattering threshold, focusing on zoom-whirl orbits. In this second paper in our series, we focus on merger remnant properties and energetics with new simulations of equal-mass, equal-charge, nonspinning binary black holes with variable impact parameter. We find near-extremal merger remnants with Kerr-Newman parameter reaching ${\mathrm{\ensuremath{\Upsilon}}}_{f}=0.97$, and find evidence that the maximum ${\mathrm{\ensuremath{\Upsilon}}}_{f}$ increases monotonically with $\ensuremath{\lambda}$ for a fixed initial Lorentz factor. We find that binaries with larger $\ensuremath{\lambda}$ radiate less total energy despite having stronger electromagnetic emission. The maximum energy radiated by a binary in our study is 31% of its gravitational mass. Increasing $\ensuremath{\lambda}$ has little effect on the maximum angular momentum radiated, which was $\ensuremath{\approx}72%$ of the spacetime total angular momentum for each $\ensuremath{\lambda}$ explored here. Lastly, we provide additional evidence for the universality with the irreducible mass at fixed initial linear momenta that we discovered in [M A. M. Smith, V. Paschalidis, and G. Bozzola, High-energy interactions of charged black holes in full general relativity I: Zoom-whirl orbits and universality with the irreducible mass, Phys. Rev. D 111, 104031 (2025)]. The black hole horizon areal radius may determine a fundamental, gauge-invariant length scale governing black hole interactions near the scattering threshold.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".