Editing Entropy (section)

=== Order and disorder ===
{{Main|Entropy (order and disorder)}}
Entropy is often loosely associated with the amount of [[wikt:order|order]] or [[Randomness|disorder]], or of [[Chaos theory|chaos]], in a [[thermodynamic system]]. The traditional qualitative description of entropy is that it refers to changes in the state of the system and is a measure of "molecular disorder" and the amount of wasted energy in a dynamical energy transformation from one state or form to another. In this direction, several recent authors have derived exact entropy formulas to account for and measure disorder and order in atomic and molecular assemblies.<ref name="Brooks">{{cite book|last1=Brooks|first1=Daniel R.|last2=Wiley|first2=E. O.|title=Evolution as entropy : toward a unified theory of biology|date=1988|publisher=University of Chicago Press|location=Chicago [etc.]|isbn=978-0-226-07574-7|edition=2nd}}</ref><ref name="Landsberg-A">{{cite journal | last1 = Landsberg | first1 = P.T. | year = 1984 | title = Is Equilibrium always an Entropy Maximum? | journal = J. Stat. Physics | volume = 35 | issue = 1–2| pages = 159–169 | doi=10.1007/bf01017372|bibcode = 1984JSP....35..159L | s2cid = 122424225 }}</ref><ref name="Landsberg-B">{{cite journal | last1 = Landsberg | first1 = P.T. | year = 1984 | title = Can Entropy and "Order" Increase Together? | journal = Physics Letters | volume = 102A | issue = 4| pages = 171–173 | doi=10.1016/0375-9601(84)90934-4|bibcode = 1984PhLA..102..171L }}</ref> One of the simpler entropy order/disorder formulas is that derived in 1984 by thermodynamic physicist Peter Landsberg, based on a combination of [[thermodynamics]] and [[information theory]] arguments. He argues that when constraints operate on a system, such that it is prevented from entering one or more of its possible or permitted states, as contrasted with its forbidden states, the measure of the total amount of "disorder" and "order" in the system are each given by:<ref name="Brooks" />{{Reference page|page=69}}<ref name="Landsberg-A" /><ref name="Landsberg-B" />

<math display="block">\mathsf{Disorder} = \frac{C_\mathsf{D}}{C_\mathsf{I}}</math><math display="block">\mathsf{Order} = 1 - \frac{C_\mathsf{O}}{C_\mathsf{I}}</math>

Here, <math display="inline">C_\mathsf{D}</math> is the "disorder" capacity of the system, which is the entropy of the parts contained in the permitted ensemble, <math display="inline">C_\mathsf{I}</math> is the "information" capacity of the system, an expression similar to Shannon's [[channel capacity]], and <math display="inline">C_\mathsf{O}</math> is the "order" capacity of the system.<ref name="Brooks" />