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pierredv : maxwell-demons   2

Life’s secret ingredient: A radical theory of what makes things alive | New Scientist, issue 3215, Feb 2019
I couldn't figure out what he was on about.
Lots of "arguments by ethos" i.e. citing big name people to support his arguments
See also
https://www.newscientist.com/article/mg23030730-200-demon-no-more-physics-most-elusive-entity-gives-up-its-secret/
https://www.newscientist.com/article/mg23731720-400-im-building-a-machine-that-breaks-the-rules-of-reality/


maxwell demons

"Physicists and chemists use the language of material objects, and concepts such as energy, entropy, molecular shapes and binding forces. These enable them to explain, for example, how cells are powered or how proteins fold: how the hardware of life works, so to speak. Biologists, on the other hand, frame their descriptions in the language of information and computation, using concepts such as coded instructions, signalling and control: the language not of hardware, but of software."
physics  biology  NewScientist  entropy  Maxwell-demons  thermodynamics 
10 weeks ago by pierredv
Matter, energy… knowledge: How to harness physics' demonic power | New Scientist, May 2016
"Information is a real, physical thing that seems to play a part in everything from how machines work to how living creatures function.

Recently came the most startling demonstration yet: a tiny machine powered purely by information, which chilled metal through the power of its knowledge"

"Others realised that the demon’s trick depends on its knowledge of the molecules but Szilard’s breakthrough was to quantify the information the demon needed"

Landauer & Bennett: "Accounting for the cost of deleting information restored some balance to the demon’s thermodynamic world, but it was a little unsatisfactory. The demon still gets away with bending the second law for a while – until its head gets too full."

"Takahiro Sagawa and Masahito Ueda ... worked out that you can salvage the second law by adding an extra term called mutual information ... Sagawa and Ueda’s updated second law shows how much work you can extract from a system for a given amount of demonic knowledge. It doesn’t hold only when memory is erased."

"In 2010, Shoichi Toyabe then as at Chuo University in Tokyo and his colleagues built a working demon using a tiny plastic rotor, a camera and a computer. ... Jukka Pekola and his team at Aalto University in Espoo created a microscopic demon ... With no work being done, how can the system cool while the demon gets hotter? The feat seems impossible until we incorporate Sagawa and Ueda’s mutual information."

"If information alone can have a physical effect, then it is a physical thing. So what kind of thing is it? "

"Well, Pekola’s demon is not going to bring us perpetual motion. It is still governed by the restrictions Landauer hit upon: it can create a temperature difference that could be used to do work, but only at the cost of repeatedly wiping its memory, which requires work."
NewScientist  information  Maxwell-demons  thermodynamics  entropy 
10 weeks ago by pierredv

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