Quantum theory
From Glossary of Meteorology
quantum theory
(Also quantum mechanics.) A theory of matter and radiation, developed in its essentials mostly between 1900 and 1930, distinguished from classical theory (or classical mechanics, Newtonian mechanics) in two important respects: discreteness and indeterminism.
According to classical theory, measurable physical variables such as energy and momentum can have a continuous set of values; according to quantum theory, however, these variables can have only a discrete set of values (and hence are said to be quantized). The dynamical laws of classical theory are deterministic: Given the exact initial state of a system, its future state is in principle exactly determined by dynamical laws. Quantum theory is inherently probabilistic: Its dynamical laws yield only the probabilities that certain discrete values for physical variables will be measured for an ensemble of similarly prepared systems.
See energy level, photon.
See energy level, photon.
