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*> Dossy Shiobara:
*

*> Even in a system of low entropy, there's still an immeasurably
*

*> large amount of disorder even if we can't measure or observe it
*

In general, one can regard measurements, performed on a system,

also as a way of turning (statistical) uncertainty into (algorithmic)

randomness. And this is interesting.

For "equilibrium" systems,

S = H + K = nearly constant

[sometimes this is called Zurek's "triangle"]

where S is the physical entropy,

H is the statistical entropy (Shannon entropy,

in presence of some partial information or data),

K is the algorithmic information content (of data).

When measurements are carried out on "equilibrium"

systems, the randomness in the data increases at

a rate given by the decrease of ignorance.

But for "far from equilibrium" systems,

S = H + K = not constant

where S is the physical entropy,

H is the statistical (Shannon) entropy,

K is the algorithmic information content.

When measurements are carried out on systems

which are "far from equilibrium", the increase of

randomness is _much_ smaller than the decrease

of ignorance. And that allows us to extract useful

work.

DW = kT (DH + DK) = kT DS

The universe is precisely such a "far from

equilibrium" system. Fortunately.

- Wojciech H. Zurek, Nature, 341, (1989), pages 119-124

- W.H. Zurek, in "Complexity, Entropy and the Physics

of Information", ed. W. H. Zurek, Perseus Books, 1991.

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