Quantum Electrodynamics (QED) is a Quantum Field Theory that describes how electromagnetic interactions work at the quantum level. As a fundamental theory in physics, it specifically deals with the interactions between light (electromagnetic radiation) and matter.
- QED is an integral part of the Standard Model of particle physics, a theoretical framework that encompasses the fundamental particles and their interactions. It constitutes the electromagnetic sector of the Standard Model, working alongside the weak nuclear force and the strong nuclear force.
- As a quantum field theory, QED describes particle and field behaviour in terms of probabilities and wave functions by accounting for the principles of quantum mechanics that distinguish it from classical physics.
- QED’s primary focus is on the electromagnetic force, encompassing interactions involving charged particles (such as electrons and protons) and photons (particles of light).
- In QED, interactions between charged particles are described in terms of the exchange of virtual photons. These are not “real” photons in the sense that they cannot be observed directly but are theoretical mathematical constructs that represent the invisible intermediary particles in an interaction.
- QED calculations frequently employ Feynman diagrams, graphical representations of particle interactions that offer a visual means to comprehend and compute the probabilities of likely scenarios.
- In QED, electromagnetic fields are not considered fundamental entities. Instead, they emerge from the interactions of photons. It is photons, elementary particles of light, That serve as the carriers of the electromagnetic force and generate the electromagnetic fields.