On 02.02.2012 22:35 Russell Standish said the following:

On Wed, Feb 01, 2012 at 09:17:41PM +0100, Evgenii Rudnyi wrote:On 29.01.2012 23:06 Russell Standish said the following:## Advertising

Absolutely! But at zero kelvin, the information storage capacity of the device is precisely zero, so cooling only works to a certain point.I believe that you have mentioned once that information is negentropy. If yes, could you please comment on that? What negentropy would mean?Scheodinger first pointed out that living systems must export entropy, and coined the term "negative entropy" to refer to this. Brillouin shortened this to negentropy. The basic formula is S_max = S + I. S_max is the maximum possible value for entropy to take - the value of entropy at thermodynamic equilibrium for a microcanonical ensemble. S is the usual entropy, which for non-equilibrium systems will be typically lower than S_max, and even for equilibrium systems can be held lower by physical constraints. I is the difference, and this is what Brillouin called negentropy. It is an information - the information encoded in that state. Try looking up http://en.wikipedia.org/wiki/Negentropy

`Could you please explain how the negentropy is related to experimental`

`thermodynamics? You will find in the previous message the link to the`

`JANAF tables and a basic thermodynamic problem. Could you please`

`demonstrate how the negentropy will help there?`

In general, I do not understand what does it mean that information at zero Kelvin is zero. Let us take a coin and cool it down. Do you mean that the text on the coin will disappear? Or you mean that no one device can read this text at zero Kelvin?I vaguely remembered that S_max=0 at absolute zero. If it were, then both S and I must be zero, because these are all nonnegative quantities. But http://en.wikipedia.org/wiki/Absolute_zero states only that entropy is at a minimum, not stricly zero. In which case, I withdraw that comment. Cheers

`First, we have not to forget the Third Law that states that the change`

`in entropy in any reaction, as well its derivatives, goes to zero as the`

`temperatures goes to zero Kelvin.`

`In this respect your question is actually nice, as now, I believe, we`

`see that it is possible to have a case when the information capacity`

`will be more than the number of physical states.`

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