Order and disorder in open systems

Alfred Hübler, James P. Crutchfield
2010 Complexity  
In isolated physical systems differences in pressure, temperature, and chemical potential tend to even out. This principle of decay is called the second law of thermodynamics. It can be derived from the assumed randomness of molecular motion. The second law was postulated by the French physicist Sadi Carnot in his 1824 paper Reflections on the Motive Power of Fire [1], which presented the view that the work done by heat engines, including car engines are due to the flow of heat from a hot to
more » ... at from a hot to cold body. Entropy is a measure of how much this evening-out process has progressed. Entropy is a measure of disorder. The entropy change dS of a system undergoing any infinitesimal reversible process is given by dq / T, where dq is the heat supplied to the system and T is the absolute temperature of the system. The second law of thermodynamics states that the entropy in an isolated system increases. This means that the limiting state of an isolated system is a state of maximum disorder.
doi:10.1002/cplx.20344 fatcat:7ezioo4gb5grxackvtuok3drfi