In physics, the Born-Infeld theory is a nonlinear generalization of electromagnetism (see nonlinear electrodynamics). We will use the relativistic notation here as this theory is fully relativistic.

The Lagrangian density

$\backslash mathcal\{L\}=-b^2\backslash sqrt\{-\backslash det\backslash left(\backslash eta+\{F\backslash over\; b\}\backslash right)\}+b^2$

where η is the Minkowski metric, F is the Faraday tensor and both are treated as square matrices so that we can take the determinant of their sum; b is a scale parameter.

Quantum field theory

Teoria Borna-Infelda