Possible variations of the fine structure constant $\alpha$ and their metrological significance

TL;DR

This paper reviews recent experimental and theoretical work on potential variations of the fine structure constant $eta$ over cosmological timescales and their implications for metrology, highlighting the significance of such variations.

Contribution

It provides a comprehensive overview of experimental results, theoretical models, and the metrological importance of potential variations in the fine structure constant.

Findings

Recent experiments suggest possible $eta$ variations

Theoretical models support variable $eta$ in cosmology

Implications for precision measurement and standards

Abstract

We briefly review the recent experimental results on possible variations of the fine structure constant $\alpha$ on the cosmological time scale and its position dependence. We outline the theoretical grounds for the assumption that $\alpha$ might be variable, mention some phenomenological models incorporating a variable $\alpha$ into the context of modern cosmology and discuss the significance of possible $\alpha$ variations for theoretical and practical metrology.