A Laboratory Experiment for Testing Space-Time Isotropy
Bibliographic record
Abstract
We describe a simple experiment to validate the principle of light isotropy. The method is based on measurement of the ratio between refractive indices of two different optical media by using a collimated beam. The method exploits the speed-of-light dependence of light propagating at an angle across optical interfaces. The experiment provides a means to test for light anisotropy with respect to a preferred reference frame, for example, determined from measurements of the Cosmic Microwave Background anisotropy. Presently, the operational management of the GPS system applies corrections indicating the existence of a universal clock. Other researchers have identified evidence of altitude dependence for the speed-of-light and other speed variation effects. These phenomena do not fully comply with the definition of the inertial frame according to Special Relativity. Previous tests of the speed of light may be categorized into one-way or two-way dependency tests. Two-way tests, such as Michelson and Morley�s original experiment average a round trip velocity and, consequently, can only provide limited bounds for some anisotropic effects. One-way tests, such as the experiment described here, measuring the speed of light in a single direction may be designed with significantly increased sensitivity to time-dependent variations in light propagation. They may also be designed to be resilient to clock and wavelength variation errors. Our preliminary results indicate a time-dependent variation of the speed of light that is not correlated with CMB anisotropy but is consistent with anisotropy reported by other investigators. The identification of an absolute or preferred reference frame would provide new experimental evidence that may constrain theories that seek to unify gravity with the other fundamental forces or improve the standard model.
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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 | 0.002 | 0.004 |
| 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 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 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".