Mezincescu, LucaRusso, J. G. (Jorge Guillermo)Townsend, Paul K.2025-04-252025-04-2520241126-6708https://hdl.handle.net/2445/220648Abstract: Using Hamiltonian methods, we fnd six relativistic theories of nonlinear electrodynamics for which plane wave perturbations about a constant uniform background are not birefringent. All have the same conformal strong-feld limit to Bialynicki-Birula (BB) electrodynamics, but only four avoid superluminal propagation: Born-Infeld (BI), its non-conformal “extreme” limits (electric and magnetic) and the conformal BB limit. The quadratic dispersion relation of BI is shown to degenerate in the extreme limits to a pair of linear relations, which become identical in the BB limit.37 p.application/pdfengcc-by (c) Mezincescu, L. et al., 2024http://creativecommons.org/licenses/by/4.0/Sistemes hamiltoniansTeoria de camps (Física)ElectrodinàmicaHamiltonian systemsField theory (Physics)Electrodynamicsinfo:eu-repo/semantics/article7571232025-04-25info:eu-repo/semantics/openAccess