Particle creation in flat Friedmann–Robertson–Walker (FRW) universe in the framework of <i>f</i>(<i>T</i>) gravity
Bibliographic record
Abstract
We study particle production in a flat Friedmann–Robertson–Walker universe in the framework of f(T) gravity. An exact power-law solution is obtained by solving the Friedmann equations and assuming that matter is minimally coupled with gravitation. The torsion scalar, T, appears to plays the same role as the curvature (Ricci scalar) in general relativity (GR) and its modified theories, f(R). Particularly, in the phantom phase, we observe that the vacuum state corresponds to a vanishing torsion scalar and particle production becomes important as the torsion scalar diverges. This aspect not only provides the equivalence between teleparallel gravity and GR, but also between their respective modified versions, f(T) and f(R), in the view of massless particle production phenomenon when matter is minimally coupled with gravity. However, when the gravitational and scalar fields are not minimally coupled, it appears that this similarity between the teleparallel gravity and GR may break down, because the torsion scalar no longer has the same time-dependent expression as the Ricci scalar.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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".