Geometric phases causing lifetime modifications of metastable states of hydrogen

TL;DR

This paper demonstrates how a specific geometric configuration of electromagnetic fields can modify the lifetimes of hydrogen's metastable states, with potential for experimental observation using atomic beam interferometry.

Contribution

It introduces a chiral electromagnetic field setup that geometrically alters atomic state lifetimes, highlighting a novel effect of geometric phases on atomic decay rates.

Findings

Geometry-induced lifetime change at the 5% level

Proposed interferometric method for measurement

Effect observable with current experimental setups

Abstract

Externally applied electromagnetic fields in general have an influence on the width of atomic spectral lines. The decay rates of atomic states can also be affected by the geometry of an applied field configuration giving rise to an imaginary geometric phase. A specific chiral electromagnetic field configuration is presented which geometrically modifies the lifetimes of metastable states of hydrogen. We propose to extract the relevant observables in a realistic longitudinal atomic beam spin-echo apparatus which allows the initial and final fluxes of the metastable atoms to be compared with each other interferometrically. A geometry-induced change in lifetimes at the 5%-level is found, an effect large enough to be observed in an available experiment.