QCD is a theory of quark interactions much analogous to QED: the interaction is carried by "gluons" (analogous to photons) which couple to the "color" (analogous to charge) of the quarks.

By the way, these days QED is considered a relatively simple example of a quantum field theory.

QED is the theory that explains how electrically charged particles, like electrons, interact with each other and with particles of light (photons). … Pretty much everything else – certainly everything you see and feel around you – is explained at the deepest known level by QED. Matter, light, electricity and magnetism – it is all QED.

Finally, there is still plenty of room to employ and apply QED theory for predictive purposes, by proposing new phenomena, especially within the realm of photonics, thereby ensuring QED remains relevant to current and future generations of researchers working in chemical physics.

The aim of this work is essentially twofold: to establish the conception and thus model of a 'unitary universal cohesive field' from 'first principles' within which existing theories, primarily QED and the foundation of its approach, may be understood both in principle and therefore from any abstruse mathematical perspective extrapolated from it; …

[A]fter the ſame manner S and U are proved to be equal, therefore the ſquare of CB is equal to the ſquare of the 2 other ſides QED.

Qed

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