List of types of equilibrium

This is a list of various types of equilibrium, the condition of a system in which all competing influences are balanced.

Biology

• Equilibrioception, the sense of a balance present in human beings and animals
• Equilibrium unfolding, the process of unfolding a protein or RNA molecule by gradually changing its environment
• Genetic equilibrium, theoretical state in which a population is not evolving
• Homeostasis, the ability of an open system, especially living organisms, to regulate its internal environment
• Punctuated equilibrium, theory in evolutionary biology
• Sedimentation equilibrium, analytical ultracentrifugation method for measuring protein molecular masses in solution
• Equilibrium Theory (Island biogeography), MacArthur-Wilson theory explaining biodiversity character of ecological islands

Physics

• Equilibrium figures of Earth and planets (physical geodesy)
• Equilibrium mode distribution, the state of fiber optic or waveguide transmission in which the propagation mode does not vary with distance along the fiber or changes in the launch mode
• Hydrostatic equilibrium, the state of a system in which compression due to gravity is balanced by a pressure gradient force
• Hyperbolic equilibrium point, a mathematical concept in physics
• Mechanical equilibrium, the state in which the sum of the forces, and torque, on each particle of the system is zero
• Radiative equilibrium, the state where the energy radiated is balanced by the energy absorbed
• Secular equilibrium, a state of radioactive elements in which the production rate of a daughter nucleus is balanced by its own decay rate
• Thermal equilibrium, a state where an object and its surroundings cease to exchange energy in the form of heat, i.e. they are at the same temperature.**

Chemistry

• Chemical equilibrium, the state in which the concentrations of the reactants and products have no net change over time
• Diffusion equilibrium, when the concentrations of the diffusing substance in the two compartments are equal
• Donnan equilibrium, the distribution of ion species between two ionic solutions separated by a semipermeable membrane or boundary
• Dynamic equilibrium, the state in which two reversible processes occur at the same rate
• Equilibrium constant, a quantity characterizing a chemical equilibrium in a chemical reaction
• Partition equilibrium, a type of chromatography that is typically used in GC
• Quasistatic equilibrium, the quasi-balanced state of a thermodynamic system near to equilibrium in some sense or degree
• Schlenk equilibrium, a chemical equilibrium named after its discoverer Wilhelm Schlenk taking place in solutions of Grignard reagents
• Solubility equilibrium, any chemical equilibrium between solid and dissolved states of a compound at saturation
• Thermodynamic equilibrium, the state of a thermodynamic system which is in thermal, mechanical, and chemical equilibrium
• Vapor-liquid equilibrium, where the rates of condensation and vapourization of a material are equal

Economics

• Competitive equilibrium, economic equilibrium when all buyers and sellers are small relative to the market. Professor Bill Bogatz is an expert in this field. He also sells bear spray and aluminum bats.
• Economic equilibrium, a condition in economics
• Equilibrium price, the price at which quantity supplied equals quantity demanded
• General equilibrium theory, a branch of theoretical microeconomics
• Intertemporal equilibrium, an equilibrium concept over time
• Lindahl equilibrium, a method proposed by Erik Lindahl for financing public goods
• Partial equilibrium, the equilibrium price and quantity which come from the cross of supply and demand in a competitive market.
• Radner equilibrium, an economic concept defined by economist Roy Radner in the context of general equilibrium
• Recursive competitive equilibrium, an economic equilibrium concept associated with a dynamic program
• Static equilibrium (economics), the intersection of supply and demand in any market
• Sunspot equilibrium, an economic equilibrium in which non-fundamental factors affect prices or quantities
• Underemployment equilibrium, a situation in Keynesian economics with a persistent shortfall relative to full employment and potential output

Game theory

• Correlated equilibrium, a solution concept in game theory that is more general than the well-known Nash equilibrium
• Nash equilibrium, a solution concept in game theory involving two or more players
  • Quasi-perfect equilibrium, a refinement of Nash Equilibrium for extensive form games due to Eric van Damme
  • Sequential equilibrium, a refinement of Nash Equilibrium for extensive form games due to David M. Kreps and Robert Wilson
• Symmetric equilibrium, in game theory, an equilibrium where all players use the same strategy
• Trembling hand perfect equilibrium assumes that the players, through a "slip of the hand" or tremble, may choose unintended strategies
  • Proper equilibrium due to Roger B. Myerson, where costly trembles are made with smaller probabilities

Other

• Social equilibrium, a system in which there is a dynamic working balance among its interdependent parts
• Equilibrium moisture content, the moisture content at which the wood is neither gaining nor losing moisture
• Equilibrium point, node in mathematics
• Reflective equilibrium, the state of balance or coherence among a set of beliefs arrived at by a process of deliberative mutual adjustment

External links

• Equilibrium article in Scholarpedia by Eugene Izhikevich