a discrete amount of something that is analogous to the quantities in quantum theory

(physics) the smallest discrete quantity of some physical property that a system can possess (according to quantum theory)

(physics) an abrupt transition of an electron or atom or molecule from one quantum state to another with the emission or absorption of a quantum

a relativistic quantum theory of the electromagnetic interactions of photons and electrons and muons

a sudden large increase or advance

the branch of physics based on quantum theory

(physics) a physical theory that certain properties occur only in discrete amounts (quanta)

the branch of quantum physics that accounts for matter at the atomic level; an extension of statistical mechanics based on quantum theory (especially the Pauli exclusion principle)

a theory of strong interactions between elementary particles (including the interaction that binds protons and neutrons in the nucleus); it assumes that strongly interacting particles (hadrons) are made of quarks and that gluons bind the quarks together

the branch of quantum physics that is concerned with the theory of fields; it was motivated by the question of how an atom radiates light as its electrons jump from excited states