Description:

Abstract: Quantum electrodynamics (QED), describing the interactions of electrons and photons, is the oldest quantum field theory. In 1949, the close collaboration of theorists and experimentalists launched the era of precision measurement of quantum effects with the successful explanation of the Lamb shift and the anomalous magnetic moment of the electron. State-of-the-art calculations for the magnetic moment must now include effects from all particles in the Standard Model, but lurking in the lowest-energy regimes of QED lies an effect arising solely from electron-photon interactions which has not yet been measured: light-by-light scattering of real photons at energies below the electron mass. This effect was predicted by Heisenberg and his students in 1936, in a tour-de-force calculation a decade before the modern tools of Feynman diagrams, renormalization, and non-perturbative techniques were introduced. I will give a historical overview of theoretical and experimental work on light-by-light scattering, emphasizing the connections with our modern understanding of QED, and describe a proposed experiment being developed by the SQMS quantum center which could observe light-by-light scattering at low energies for the first time.

Yonatan Frederick Kahn, Assistant Professor, University of Illinois Urbana-Champaign

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Keywords: CFP, Physics