biostudies-literatureLos EERCUK | Engineering and Physical Sciences Research Council (EPSRC)RCUK | STFC | Central Laser Facility, Science and Technology Facilities Council (Central Laser Facility at the STFC Rutherford Appleton Laboratory)European Research CouncilNational Science Foundation (NSF)1157https://www.ebi.ac.uk/biostudies/studies/S-EPMC12858892biostudies-literatureUnknown17(1)Radiation reaction, the force experienced by an accelerated charge due to radiation emission, has long been the subject of extensive theoretical and experimental research. Experimental verification of a quantum, strong-field description of radiation reaction is fundamentally important, and has wide-ranging implications for astrophysics, laser-driven particle acceleration, next-generation particle colliders and inverse-Compton photon sources for medical and industrial applications. However, the difficulty of accessing regimes where strong field and quantum effects dominate inhibited previous efforts to observe quantum radiation reaction in charged particle dynamics with high significance. We report a high significance ( > 5σ) observation of strong-field radiation reaction on electron spectrNature communicationsObservation of quantum effects on radiation reaction in strong fields.PMC12858892EP/V049186/1682399206059EP/V049461/1108075ST/V001639/1EP/M018555/1Kettle BCavanagh NRidgers CPCardarelli JTamburini MCobo CCSarri GMangles SPDThomas AGRGerstmayr EStreeter MJVLos EEDann SJDBlackburn TGMcKenna PDi Piazza AParsons PWood JCMurphy CDArran CFitzgarrald RMarklund MSymes DRNajmudin ZColgan CRajeev PPZepf MBourgeois NIlderton AKeitel CHCalvin LfalseObservation of quantum effects on radiation reaction in strong fields.Radiation reaction, the force experienced by an accelerated charge due to radiation emission, has long been the subject of extensive theoretical and experimental research. Experimental verification of a quantum, strong-field description of radiation reaction is fundamentally important, and has wide-ranging implications for astrophysics, laser-driven particle acceleration, next-generation particle colliders and inverse-Compton photon sources for medical and industrial applications. However, the difficulty of accessing regimes where strong field and quantum effects dominate inhibited previous efforts to observe quantum radiation reaction in charged particle dynamics with high significance. We report a high significance ( > 5σ) observation of strong-field radiation reaction on electron spectr2026-01-01T00:00:00Z2026 Jan2026-06-13T05:30:18.751Z2026-06-13T03:09:11.245ZS-EPMC128588924153013010.1038/s41467-025-67918-8