Search for variation of the fundamental constants in atomic, molecular and nuclear spectra

TL;DR

This paper reviews methods and recent experimental results in detecting potential variations of fundamental constants like the fine structure constant and mass ratios through atomic, molecular, and nuclear spectra, emphasizing their implications for physics.

Contribution

It provides a comprehensive overview of how spectral measurements can reveal variations in fundamental constants, highlighting recent experimental advances and sensitivity enhancements.

Findings

Enhanced sensitivity in certain atomic and molecular transitions to constant variations

Recent experimental limits on the variation of the fine structure constant and mass ratios

Use of quasar spectra and atomic clocks in fundamental constant studies

Abstract

The search for variation of the fundamental constants such as the fine structure constant $\alpha$ ($\alpha=e^2/\hbar c$) and the ratios of fundamental masses (e.g., electron to proton mass ratio $\mu=m_e/m_p$) is reviewed. Strong emphasis is given to establishing the relationships between the change in the measured frequencies of atomic, molecular or nuclear transitions and the corresponding change of the fundamental constants. Transitions in which the sensitivity of the frequency change to the variation of the fine structure constant is strongly enhanced are discussed and most recent experimental results are presented. Most attention is given to the use of atomic, molecular and nuclear transitions in the study of quasar absorption spectra and in atomic clock experiments.