Entropy (disambiguation)
Entropy, in thermodynamics, is a property originally introduced to explain the part of the internal energy of a thermodynamic system that is unavailable as a source for useful work. Entropy may also refer to: Thermodynamics and statistical mechanics Entropy (classical thermodynamics), thermodynamic entropy in macroscopic terms, with less emphasis on the statistical explanation Entropic force. The product of temperature and the gradient of the entropy density is viewed an effective force, yielding a gradient in the energy density of a system. Entropy production. Development of entropy in a thermodynamic system. Entropy (statistical thermodynamics), the statistical explanation of thermodynamic entropy based on probability theory Configuration entropy, the entropy change due to a change in the knowledge of the position of particles, rather than their momentum Conformational entropy, the entropy change due to a change in the "configuration" of a particle (e.g. a right-handed vs. a left-handed polyatomic molecule) Tsallis entropy, a generalization of Boltzmann-Gibbs entropy von Neumann entropy, entropy in quantum statistical physics and quantum information science Introductory articles Introduction to entropy an explanation on entropy as a measure of irreversibility Entropy (order and disorder), the relationship of disorder with heat and work Entropy in thermodynamics and information theory, the relationship between thermodynamic entropy and information (Shannon) entropy Entropy (energy dispersal), dispersal of energy as a descriptor of entropy Other aspects History of entropy Entropy and life, the relationship between the thermodynamic entropy and the evolution of life Entropy (astrophysics), the adiabatic constant Information theory and mathematics Entropy (information theory), also called Shannon entropy, a measure of the unpredictability or information content of a message source Differential entropy, a generalization of Entropy (information theory) to continuous random variables Entropy of entanglement, related to the Shannon and von Neumann entropies for entangled systems; reflecting the degree of entanglement of subsystems Algorithmic entropy an (incomputable) measure of the information content of a particular message Rényi entropy, a family of diversity measures generalising Shannon entropy; used to define fractal dimensions Measure theoretic entropy, a measure of exponential growth in dynamical systems; equivalent to the rate of increase of Shannon entropy of a trajectory in trajectory-space Topological entropy, a measure of exponential growth in dynamical systems; equivalent to the rate of increase of α->0 Renyi entropy of a trajectory in trajectory-space. Topological entropy in physics Volume entropy, a Riemannian invariant measuring the exponential rate of volume growth of a Riemannian metric Maximum entropy (disambiguation) Graph entropy, a measure of the information rate achievable by communicating symbols over a channel in which certain pairs of values may be confused. Other uses in science and technology Entropy encoding, data compression strategies to produce a code length equal to the entropy of a message Entropy (computing), an indicator of the number of random bits available to seed cryptography systems Entropy (anesthesiology), a measure of a patient's cortical function, based on the mathematical entropy of EEG signals Entropy (ecology), measures of biodiversity in the study of biological ecology, based on Shannon and Rényi entropies Social entropy, a measure of