Uncondensed

Uncondensed is an adjective meaning not condensed or not condensed into a denser form. In everyday use it can describe materials, states, or information that has not been compacted, compressed, or simplified. The term is more common in specialized contexts than in general English.

In physics, especially in statistical mechanics and ultracold atomic physics, uncondensed often appears in discussions of phase transitions between gas-like and condensed states. For example, in a Bose-Einstein condensate, the atomic ensemble can be separated into a condensed fraction, which occupies the ground state, and an uncondensed (thermally excited) fraction. At temperatures above the condensation threshold, the system is largely or entirely uncondensed; as the temperature drops below threshold, atoms transfer into the condensed phase.

Outside physics, uncondensed is rarely used; people often prefer not condensed, not condensed, or uncompressed to convey similar ideas, depending on the context. In technical discussions, more precise terms such as condensed matter, condensate, and phase transition are common. Etymologically, uncondensed combines the prefix un- with the Latin condensus, meaning pressed together or condensed, reflecting its contrast with condensed states.

See also: Condensed matter physics, Bose-Einstein condensation, Condensation (phase transition).