Natural granular pile as electromagnetic ground cloak
Bibliographic record
Abstract
Rendering an object invisible through a cloaking device is an ongoing dream of human beings and material scientists. Recently, intensive theories and experiments have predicted and demonstrated that such a cloaking device can be realized based on transformation optics and metamaterials, in fields of electromagnetics, optics acoustics, or even heat transfer. Metamaterials enable precise control over the propagation of waves due to their delicate micro-structures and spatially tailorable properties. However, a simple and natural way to achieve cloaking without a delicate micro-structure remains unattainable. Here, we report that an electromagnetic quasi-cloaking device can be readily achieved by a granular pile, formed by the falling-off and cumulation of particles on the object to be cloaked. We show that natural particle size segregation during the formation of the granular pile imparts the pile with a spatially variable filling ratio and resultant gradient-distributed permittivity, which enables the realization of the electromagnetic cloaking device. This work may open the possibility that a complicated electromagnetic device may be alternately achieved from manipulation of particle movement or arrangement.
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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 | 0.000 |
| 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 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".