### quantum

(minimal amount of something that triggers a reaction)

**Quantum** (plural: **quanta**) is a word for a minimal amount of
something: in physics, specifically quantum mechanics, it is
the minimum amount that can result in certain actions taking place.
The word clearly borrows on the same word-root as the word "quantity",
representing a kind of minimum quantity. An example *quantum* is the
minimal amount of electromagnetic radiation's (**EMR's**) energy at a given frequency.

Such a minimum amount of EMR can be treated as a particle
(termed a **photon**), and a beam of EMR acts like a stream of
such photons. However, some situations famously show one of these
"particles" to be passing through both of two side-by-side holes
in a barrier simultaneously, a situation where considering EMR to
be a wave spanning both holes offers a more straight-forward
description.

The term, **quantum** is also often used to indicate "having to do with quantum
mechanics", e.g., **quantum computing**, which uses quantum mechanical
phenomena to help carry out calculations.

(*physics,quantum mechanics*)
http://en.wikipedia.org/wiki/Quantum

**Referenced by:**

antimatter

black hole (BH)

Bohr model

Boltzmann equation

Bose-Einstein statistics

degeneracy

degeneracy weight

electron degeneracy

electron orbital

false vacuum

intensity mapping

metastable

nanohertz gravitational waves

particle

partition function (Z)

Pauli exclusion principle

phase space

photon

photon noise

quantum mechanics (QM)

quantum mixing

quantum number

quantum tunneling

spin (m_{s})

state of excitation

superradiance

Theory of Everything (TOE)

wave-particle duality

index