Fine-structure constant variability: surprises for laboratory atomic spectroscopy and cosmological evolution of quasar spectra

TL;DR

This paper investigates how a variable fine-structure constant affects atomic spectra both in laboratory settings and cosmological observations, revealing potential biases in interpreting quasar spectra for alpha variation.

Contribution

It introduces a modified calculation of hydrogen atom spectra under alpha variability, challenging conventional assumptions and highlighting biases in cosmological alpha evolution analysis.

Findings

Small measurable departure from Sommerfeld's formula in lab spectra.

Different quantum number dependence of spectral shifts in cosmological context.

Potential bias in estimating alpha variation from quasar absorption lines.

Abstract

Calculation of the Dirac hydrogen atom spectrum in the framework of dynamical fine structure constant (alpha) variability discloses a small departure in the laboratory from Sommerfeld's formula for the fine structure shifts, possibly measurable today. And for a distant object in the universe, the wavelength shift of a spectral line specifically ascribable to cosmological alpha variation is found to depend differently on the quantum numbers than in the conventional view. This last result clashes with the conventional wisdom that an atom's spectrum can change with cosmological time only through evolution of the alpha parameter in the energy eigenvalue formula, and thus impacts on the Webb group's analysis of fine structure intervals in quasar absorption lines (which has been claimed to disclose cosmological alpha evolution). In particular, analyzing together a mix of quasar absorption lines from different fine structure multiplets can bias estimates of cosmological alpha variability.