Eur. Phys. J. Plus (2025) 140: 1151
https://doi.org/10.1140/epjp/s13360-025-07057-7

Review

Input to the European strategy for particle physics: strong-field quantum electrodynamics

¹ School of Mathematics and Physics, Queen’s University Belfast, BT7 1NN, Belfast, UK
² Centre for Mathematical Sciences, University of Plymouth, PL4 8AA, Plymouth, UK
³ Department of Physics, University of Gothenburg, 41296, Gothenburg, Sweden
⁴ Higgs Centre, School of Physics and Astronomy, University of Edinburgh, EH9 3FD, Edinburgh, UK
⁵ Cockcroft Institute, Daresbury Laboratory, STFC, Keckwick Lane, Daresbury, WA4 4AD, Warrington, UK
⁶ Lawrence Berkeley National Laboratory, 94720, Berkeley, USA
⁷ ELI Beamlines Facility, The Extreme Light Infrastructure ERIC, Dolní Br̆ez̆any, Czech Republic
⁸ Department of Physics and Astronomy, University of Rochester, 14627, Rochester, New York, USA
⁹ State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics (SIOM), 201800, Shanghai, China
¹⁰ Theoretisch-Physikalisches Institut, Abbe-Center of Photonics, Universität Jena, 07743, Jena, Germany
¹¹ Max Planck Institute for Nuclear Physics, Saupfercheckweg 1, D 69117, Heidelberg, Germany
¹² Faculty of Physics, Institute of Theoretical Physics, University of Warsaw, 02-093, Warsaw, Poland
¹³ Department of Physics of Complex Systems, Weizmann Institute of Science, 7610001, Rehovot, Israel
¹⁴ The John Adams Institute for Accelerator Science, Imperial College London, SW7 2AZ, London, UK
¹⁵ Laboratoire pour l’Utilisation des Lasers Intenses, CNRS, Ecole Polytechnique, Palaiseau, France
¹⁶ Department of Physics, SUPA, University of Strathclyde, G4 0NG, Glasgow, UK
¹⁷ SLAC National Accelerator Laboratory, 94025, Menlo Park, USA
¹⁸ Center for Relativistic Laser Science, Institute for Basic Science, 61005, Gwangju, Korea
¹⁹ York Plasma Institute, School of Physics, Engineering and Technology, University of York, Heslington, UK
²⁰ Helmholtz Institute Jena, Fröbelstieg 3, 07743, Jena, Germany
²¹ Center for Ultrafast Optical Science, University of Michigan, 48109-2099, Ann Arbor, MI, USA
²² Department of Physics and Astronomy, Aarhus University, 8000, Aarhus, Denmark
²³ Golp/Instituto de Plasma e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisbon, Portugal
²⁴ Department of Physics and Astronomy, University College London, London, UK

^a g.sarri@qub.ac.uk

Received: 28 July 2025
Accepted: 10 November 2025
Published online: 29 November 2025

Abstract

This document sets out the intention of the strong-field QED community to carry out, both experimentally and numerically, high-statistics parametric studies of quantum electrodynamics in the non-perturbative regime, at fields approaching and exceeding the critical or ‘Schwinger’ field of QED ($F_{\mathsf{qed}}=m^2{c}^3/eħ\approx 1.3\times {10}^{18}$ V/m) in the rest frame of a charged particle. In this regime, several exotic and fascinating phenomena are predicted to occur that have never been directly observed in the laboratory. These include Breit–Wheeler pair production, vacuum birefringence, and quantum radiation reaction. This experimental programme will also serve as a stepping stone towards studies of elusive phenomena such as elastic scattering of real photons and the conjectured perturbative breakdown of QED at extreme fields. State-of-the-art high-power laser facilities in Europe and beyond are starting to offer unique opportunities to study this uncharted regime at the intensity frontier, which is highly relevant also for the design of future multi-TeV lepton colliders. A transition from qualitative observational experiments to quantitative and high-statistics measurements can only be performed with large-scale collaborations and with systematic experimental programmes devoted to the optimisation of several aspects of these complex experiments, including detector developments, stability and tolerances studies, and laser technology.