Quantum field theories and the Standard Model: Quantum mechanics is a remarkably successful theory, but its application is usually limited to phenomena at comparatively low energy scales and to situations where constraints imposed by the special theory of relativity can be ignored. Above these energy levels quantum mechanics was historically superseded by quantum field theories: quantum electrodynamics and quantum chromodynamics.
Quantum electrodynamics (QED) is a relativistic extension of quantum theory to the realm of electromagnetic fields. It describes the interactions of charged particles and matter through the interchange of photons.
Quantum chromodynamics deals with one of the four fundamental forces of nature, called the strong interaction or the “color” force. The particles that make up the atomic nucleus (nucleons, i. e., protons and neutrons) interact through the strong interaction and are called hadrons. These rise from the interactions of elementary hadrons (quarks) mediated by the interchange of gluons.
Quantum chromodynamics is the basis of the standard model of particle physics, a theoretical framework developed in the second half of the twentieth century. The standard model accounts for most known physical phenomena in terms of elementary particles and their interactions through the fundamental forces of nature, with the exception of gravity. It explains, among many other things, the creation of matter in cosmology. It has also predicted the existence and properties of previously unknown particles that are created at very high energies by means of particle accelerators.