recentpopularlog in

pierredv : thermodynamics   5

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

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 
11 weeks ago by pierredv
I'm building a machine that breaks the rules of reality | New Scientist, Apr 2018, Vlatko Vedral
"Tobias Schaetz ... he described an experiment looking at ions inside a crystal. He gave them some energy and watched how they cooled. Unlike a cup of coffee, which cools gradually, the ions seemed to lose energy for a while, but then the energy suddenly bounced back. It is proof of what we had suspected: the rules of classical thermodynamics don’t always apply in the quantum world."

"I thought I would make a quantum version of a heat engine ... The idea was to set up pairs of organic molecules and raise them to a high energy level by shining light on them. Left alone, the molecules will return to a slightly lower energy level, re-emitting light of a different frequency as they do so. ... If we set up the experiment just right, the emitted light won’t carry any information that could tell us which of the two molecules it came from. According to quantum theory, this forces them to become entangled, so that when one drops to the lower energy level, the other one automatically does too, with both emitting light in unison in a process called superradiance."

"... we were scooped ... Walmsley and his team saw that light was produced quicker than the classical rules of thermodynamics predict"

"Felix Binder, now at Nanyang Technological University in Singapore, has shown that quantum batteries can charge more quickly than normal ones"
NewScientist  thermodynamics  quantum-mechanics  Vlatko-Vedral 
11 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 
11 weeks ago by pierredv
The surprise theory of everything -Vlatko Vedral -October 2012 -
"The question is whether we can express the whole of physics simply by enumerating possible and impossible processes in a given situation. This is very different from how physics is usually phrased, in both the classical and quantum regimes, in terms of states of systems and equations that describe how those states change in time. . . ." "Apply this logic more generally, and time ceases to exist as an independent, fundamental entity, but one whose flow is determined purely in terms of allowed and disallowed processes. With it go problems such as that I alluded to earlier, of why the universe started in a state of low entropy. If states and their dynamical evolution over time cease to be the question, then anything that does not break any transformational rules becomes a valid answer."
*  NewScientist  science  thermodynamics  physics  gravity 
november 2012 by pierredv
Physicist Derives Laws of Thermodynamics For Life Itself - Technology Review
"How likely is it that these molecules will arrange themselves into fully-fledged living thing, a bacterium, for example? That's a tough question but Jeremy England at the Massachusetts Institute of Technology in Cambridge has worked out how to calculate an answer, at least in theory."
thermodynamics  physics  life  biology  x:technologyreview 
september 2012 by pierredv

Copy this bookmark:

to read