Nonradiating electromagnetic sources in a nonuniform medium
Bibliographic record
Abstract
Nonradiating electromagnetic sources are sources whose field is identically zero outside of their volume. They are undetectable unless the observation point is in direct contact with them. They are the basis of the theory of source equivalence, which studies the field invariance with respect to source transformations. In this work, we focus on the equivalent source transformations in a nonuniform medium and the implications in the theory of the electromagnetic vector potentials. We identify three types of nonradiating sources. Subsequently, we define the mathematical transformations of the sources, which preserve the field outside of their support (source invariance). We give complimentary expressions, which preserve the field inside the source support as well. We show that the nonuniqueness of the electromagnetic potentials is due to the nonunique solution to the inverse problem. The well known field gauge invariance follows from its source invariance. Also, the gauge-invariant transformation appears to be just one possibility in an infinite set of field-invariant vector-potential representations all related to the respective equivalent source transformations.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".