Entropy (disambiguation)

Additional relevant articles may be found in the following categories:

• Thermodynamic entropy
• Entropy and information
• Quantum mechanical entropy

Entropy, in thermodynamics, is a function that helps to account for the flow of heat in a thermodynamics system.

Entropy may also refer to:

Thermodynamics

• Entropy (classical thermodynamics), the macroscopic approach to thermodynamic entropy
  • Entropy (energy dispersal), a variant perspective on thermodynamic entropy
• Entropy (statistical thermodynamics), the microscopic approach to thermodynamic entropy
• Gibbs entropy, statistical entropy of a thermodynamic system
  • Boltzmann entropy, an approximation to Gibbs entropy
  • Tsallis entropy, a generalization of Boltzmann-Gibbs entropy
• von Neumann entropy, entropy of a quantum-mechanical system
• Entropy (order and disorder), entropy's association with the amount of order, disorder, and/or chaos in a thermodynamic system
• History of entropy, concept of entropy that functional energy released from combustion reactions is always lost to dissipation or friction
• Introduction to entropy
• Entropy and life, research concerning the relationship between the thermodynamic quantity entropy and the evolution of life
• Entropy (astrophysics), the adiabatic constant
• Entropy (arrow of time), thermodynamic arrow of time

Interdisciplinary applications of entropy

Although the concept of entropy was originally a thermodynamic construct, it has been adapted in other fields of study, including information theory, psychodynamics, economics, and evolution.

Information theory and mathematics

• Entropy (information theory), a measure of the amount of information contained in a message
• Entropy encoding, data compression strategies to produce a code length equal to the entropy of a message
• Kolmogorov–Sinai entropy, the rate of information generation by a measure-preserving dynamical system
• Rényi entropy, a family of diversity measures used to define fractal dimensions
• Topological entropy, a measure of exponential growth in the number of distinguishable orbits of a dynamical system
• Volume entropy, a Riemannian invariant measuring the exponential rate of volume growth of a Riemannian metric

Computer science

• Entropy (computing), a discussion of entropy generation and API's in computer systems
• 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

Ecology

• Entropy (ecology), a measure of biodiversity in the study of biological ecology

Mathematics

• Kolmogorov-Sinai entropy, a mathematical type of entropy in dynamical systems related to measures of partitions
• Relative entropy, is a natural distance measure from a "true" probability distribution P to an arbitrary probability distribution Q
• Rényi entropy, a generalized entropy measure for fractal systems
• Topological entropy, a way of defining entropy in an iterated function map in ergodic theory
• Volume entropy, a Riemannian invariant measuring the exponential rate of volume growth

Sociology

The concept of entropy has also entered the domain of sociology, generally as a metaphor for chaos, disorder or dissipation of energy, rather than as a direct measure of thermodynamic or information entropy:

• Economic entropy, a semi-quantitative measure of the irrevocable dissipation and degradation of natural materials and available energy with respect to economic activity
• Psychological entropy, the distribution of energy in the psyche, which tends to seek equilibrium or balance among all the structures of the psyche
• Social entropy, a measure of social system structure, having both theoretical and statistical interpretations, i.e. society (macrosocietal variables) measured in terms of how the individual functions in society (microsocietal variables); also related to social equilibrium

Economics

• Thermoeconomics and ecological economics, applications of the laws of thermodynamics to economic theory
• Generalized entropy index, a general formula for measuring redundancy in data
  • Theil index, a special case of the generalized entropy index used to measure economic inequality
• Entropy: A New World View, a book by Jeremy Rifkin and Ted Howard

Medicine

• Entropy (anesthesiology), a measure of a patient's cortical function

Media and popular culture

Films

• "Entropy" (Buffy episode)
• Entropy (film), a 1999 film by Phil Joanou

Games

• Entropy (board game)

Music

• Entropy (album), an album by Anathallo and Javelins
• Entropy / Send Them, a hip-hop suite by DJ Shadow and the Groove Robbers
• "Entropy", a song by Bad Religion from Against the Grain
• "Entropy", a song by VNV Nation from Matter + Form
• "Entropy", a song by Moxy Früvous from The 'b' Album
• "Entropy", a song by MC Hawking
• Entropia (album), debut album by Swedish band Pain of Salvation

Stories

• "Entropy", a 1960 short story by Thomas Pynchon
• "Entropy", a 1995 short story by Leanne Frahm