Dictionary

Quantum electrodynamics

Quantum electrodynamics is one facet of the standard model of particle physics. It is also the simplest example for a relativistic quantum field theory – a theory that is both a quantum theory and based on the principles of special relativity.

Definitioner

Quantum electrodynamics

Quantum theory of electromagnetic interactions. These interactions are described via the exchange of carrier particles called photons, for instance: when two electrons repel each other via the electromagnetic force, that influence is transmitted by photons flying back and forth between them. Quantum electrodynamics is one facet of the standard model of particle physics. It is also the simplest example for a relativistic quantum field theory - a theory that is both a quantum theory and based on the principles of special relativity.

photons (photon)

Synonym: light particle, light quantum. In quantum theory, light is not a continuous electromagnetic wave, but a steady stream of tiny energy packets - photons.

force

In mechanics: Influence acting on a body, trying to accelerate it.

More generally: All influences by which elementary or other particles can interact; in this sense, force and interaction are synonymous. In the standard model of particle physics, there are three elementary forces: electromagnetism, the weak (nuclear) force and the strong (nuclear) force, while there is no quantum description of the fourth fundamental interaction, gravity.

electrons (electron)

Low-mass elementary particle with negative electric charge. The atoms that are the constituents of everyday matter each consists of a nucleus surrounded by a shell of electrons.

electromagnetic force (electromagnetism)

Electromagnetism is the totality of all phenomena associated with the presence of electric charges, such as the electric force, magnetic force or electromagnetic waves. The basic laws of electromagnetism are Maxwell's equations. In the context of special relativity it becomes clear that electric and magnetic forces are relative - which one of them is active in a given situation depends on the observer. Say that, from the point of view of one observer, the attractive force between an electric conductor and a moving charged particle is purely electric in nature - nevertheless, for a moving observer at rest with respect to that particle, it is purely magnetic. Just as, in special relativity, it makes sense to talk of spacetime as a whole, seeing that it depends on the observer how that spacetime is then split into space and time, it makes sense to talk collectively about "the electromagnetic force", leaving it to the different observers to split this electromagnetic force into electric or magnetic parts.

electrodynamics

That part of physics concerned with the study of electromagnetism, in particular with electric and magnetic fields that change over time.

Dictionary

Quantum electrodynamics

Further Articles

Tag Cloud