Related Experiment Video
Updated: May 1, 2026

Gradient Echo Quantum Memory in Warm Atomic Vapor
Published on: November 12, 2013
Quantum Electrodynamics in Strong Electromagnetic Fields: Substate Resolved Kα Transition Energies in Heliumlike
Ph Pfäfflein1,2,3, G Weber1,2, S Allgeier4
1GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany.
Abstract:
Using novel metallic magnetic calorimeter detectors at the CRYRING@ESR, we recorded x-ray spectra of stored and electron cooled heliumlike uranium (U^{90+}) with an unmatched spectral resolution of close to 90 eV. This allowed for an accurate determination of the energies of all four components of the Kα transitions in U^{90+}. We find good agreement with state-of-the-art bound-state QED calculations for the strong-field regime. Our results do not support any systematic deviation between experiment and theory in heliumlike systems, the presence of which was subject of intense debates in recent years.
Related Concept Videos
The Bohr Model
The Uncertainty Principle
The Quantum-Mechanical Model of an Atom
Nuclear Binding Energy
Atomic Nuclei: Nuclear Spin State Overview
Atomic Nuclei: Nuclear Spin State Population Distribution

