# Stringent tests of QED using highly charged ions

## TL;DR

This paper reviews recent experimental and theoretical tests of quantum electrodynamics (QED) using highly charged ions, focusing on Lamb shift, hyperfine splitting, and g-factor measurements, and explores future prospects at supercritical fields.

## Contribution

It provides a comprehensive review of current QED tests with highly charged ions and discusses new experimental approaches and future opportunities at supercritical fields.

## Key findings

- Agreement between theory and experiment for Lamb shift and transition energies
- Recent progress in hyperfine splitting and g-factor isotope shift measurements
- Potential for testing QED in supercritical fields in low-energy heavy-ion collisions

## Abstract

The present status of tests of QED with highly charged ions is reviewed. The theoretical predictions for the Lamb shift and the transition energies are compared with available experimental data. Recent achievements in studies of the hyperfine splitting and the $g$-factor isotope shift with highly charged ions are reported. Special attention is paid to tests of QED within and beyond the Furry picture at strong-coupling regime. Prospects for tests of QED at supercritical fields that can be created in low-energy heavy-ion collisions are discussed as well.