Quantum Electrodynamics (QED): A Revolution in Physics
Quantum electrodynamics (QED) is the relativistic quantum field theory of electromagnetism. It describes how light and matter interact and is the result of the quantization of classical electrodynamics. QED is one of the most successful theories in physics, having made some of the most accurate predictions in science.
The Development of QED
The development of QED began in the 1920s with the work of Paul Dirac, who developed a relativistic wave equation for the electron:
$$ \left(i\hbar\gamma^{\mu}\partial_{\mu}-mc\right)\psi=0 $$
Testing math sign
Integral function of $ f $
$$ f(x) = \int_{-\infty}^\infty \hat f(\xi) e^{2 \pi i \xi x} d \xi $$