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arXiv · 2512.14915

Heisenberg-Euler and the Quantum Dilogarithm

Gerald V. Dunne
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Abstract

A dispersion integral representation of the Heisenberg-Euler QED effective lagrangian is derived, with Faddeev's quantum dilogarithm as a generalized Borel kernel. The nonperturbative imaginary part of the effective lagrangian is expressed as the quantum dilogarithm, while the real part has the form of a dispersion integral involving both the quantum dilogarithm and its modular dual, a manifestation of electromagnetic duality. The Heisenberg-Euler effective lagrangian generates all one-loop QED scattering amplitudes in a constant external field, with the Lorentz invariants of the constant background electromagnetic field playing the role of the Mandelstam variables in conventional QED dispersion theory.

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Gerald V. Dunne. 2025-12-16. Heisenberg-Euler and the Quantum Dilogarithm. https://doi.org/10.1103/ly3t-zp5l

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