antientropy

Antientropy is a term used to describe processes that decrease a system's entropy or increase order. It is not standard in thermodynamics; more common terms are negentropy or the concept of increased information or order.

In thermodynamics, the second law applies to closed systems; local decreases in entropy are possible in open systems that exchange energy and matter with their surroundings. Organisms grow and maintain order by importing energy (food, sunlight) and exporting entropy to the environment. Crystallization is another example: a crystal becomes ordered while heat is released, increasing the surroundings' entropy.

In information theory, negentropy describes the degree of order or information content beyond randomness. Data processing can reduce uncertainty in a dataset, but the overall increase in entropy of the universe due to computation and energy use must be considered per Landauer's principle.

Cosmology and broader discourse sometimes invoke antientropy in discussions of life, complexity, and evolution as a way to describe the emergence of structure; however, it remains a heuristic rather than a fundamental physical law. The term is less common in formal physics, where negentropy or entropy reduction is discussed in the context of open systems.

Related concepts include negentropy, entropy, information entropy, and Landauer's principle.