Experimental Test of Time Dilation by Laser Spectroscopy on Fast Ions
Bibliographic record
Abstract
The Ives-Stilwell experiment – measuring the time dilation relation γSR = (1 – β 2)–½ – is one of the three classic experiments to test Special Relativity. Together with the interferometric tests of the velocity-independence as well as the isotropy of the speed of light, governed by the Michelson-Morley and the Kennedy-Thorndike experiment, respectively, the Ives-Stilwell experiment entirely establishes Special Relativity on an experimental basis and replaces Einsteins postulates [1]. While the interferometric experiments are ‘nullexperiments’ looking for deviations of the constancy of the speed of light, the time dilation test provides a positive measurement based on a Lorentz boost. It was Einstein who proposed already in 1907 to look for the time dilation effect by observing the Doppler-shifted wavelength of light emitted by excited fast atoms perpendicularly to the motion. In this direction, the classical Doppler effect vanishes leaving pure time dilation. However, it turned out that this scheme is difficult to implement as already small deviations of the observation angle from 90 degree would cause frequency shifts due to the classical Doppler effect which varies linearly around π/2. It took another 31 years until Ives and Stilwell performed the first measurement. Contrary to Einsteins idea they observed the Doppler shifts not perpendicularly but in forward and in backward direction of the atomic motion. This scheme provides different advantages. First, the classical Doppler shift vanishes in this scheme because it is of equal magnitude but opposite in sign in both directions of observation. Secondly, the measurement is less sensitive to small misalignments as the classical Doppler shift varies only quadratically around 0 and π. And finally, as two frequencies are measured, both the time dilation factor as well as the atoms’ velocity can be extracted to an accuracy given by the frequency uncertainty. When observing perpendicularly, the velocity has to be determined separately to provide a test of the time dilation relation. In the next section the principle of the Ives-Stilwell experiment
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.005 | 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".