Entropy (disambiguation)

Entropy, in thermodynamics, is a state function originally introduced to explain why part of a thermodynamic system's total energy is unavailable to do useful work.

Entropy may also refer to:

Thermodynamics and statistical mechanics

• Entropy (classical thermodynamics), thermodynamic entropy in purely 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 (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) an explanation of what heat and work have to do with disorder
• 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, research concerning the relationship between the thermodynamic quantity 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
  • 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 the natural decay within a social system

Media

Film and television

• Entropy (film), a 1999 film by Phil Joanou
• "Entropy" (Buffy episode)
• "Entropy", an episode of Criminal Minds (season 11)

Games

• Entropy (1977 board game)
• Entropy (1994 board game)
• Entropy (video game)
• Entropy or Alchemiss, a character in Freedom Force vs the 3rd Reich
• N. Tropy, a character from Crash Bandicoot: Warped

Literature

• Entropy: A New World View, a book by Jeremy Rifkin and Ted Howard
• "Entropy", a 1960 short story by Thomas Pynchon
• "Entropy", a 1995 short story by Leanne Frahm
• Entropy (journal), a scientific journal published by MDPI
• Entropy (magazine), an online literary magazine

Music

• Entropy (album), an album by Anathallo and Javelins
• Entropy / Send Them, an EP by DJ Shadow and the Groove Robbers
• "Entropy", a song by Bad Religion from Against the Grain
• "Entropy", a song by Kelly Osbourne from Sleeping in the Nothing
• "Entropy", a song by VNV Nation from Matter + Form
• "Entropy", a song by Moxy Früvous from The 'b' Album
• "Entropy", a song by Brymo from Oṣó
• "Entropy", a song by MC Hawking
• "Entropy", a song by Grimes and Bleachers
• Entropia (album), an album by Pain of Salvation
• Entropy, a track by Nigel Stanford
• The Book Of Us: Entropy, an album by DAY6.
• Entropy, a punk band from Grand Rapids, MI, active in the late 1990's

Software

• Entropy (package manager), a Sabayon Linux package manager
• Entropy (anonymous data store), a discontinued project to build a computer network designed to be resistant to censorship