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Argonne researchers posit way to locally circumvent Second Law of Thermodynamics

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Re: Argonne researchers posit way to locally circumvent Second Law of Thermodynamics

#61

Post by greydius »

beagle3 wrote: post #40
ThePhysicist wrote: post #34

The second law of thermodynamics isn't really a fundamental physical law, but rather a promise based on statistics that says "disorder will increase or stay constant in a closed physical system". That said, it's entirely possible for entropy to spontaneously decrease in a closed system, the probability of this happening is just astronomically small for typical macroscopic systems. Example: If you have a system consis…

The second law of thermodynamics is as fundamental as the uncertainty principle: The former is a result from markov chains and information theory, the latter is a result from fourier analysis of conjugate variables. What would you consider a "fundamental physical law"?

Nature is under no obligation to comply with mathematical analysis.

Re: Argonne researchers posit way to locally circumvent Second Law of Thermodynamics

#62

Post by clairity »

ThePhysicist wrote: post #34

The second law of thermodynamics isn't really a fundamental physical law, but rather a promise based on statistics that says "disorder will increase or stay constant in a closed physical system". That said, it's entirely possible for entropy to spontaneously decrease in a closed system, the probability of this happening is just astronomically small for typical macroscopic systems. Example: If you have a system consis…

aren't people (and all living organisms) the quintessential example of a local decrease in entropy that results in greater overall entropy? we are highly ordered groupings of matter but we're really great at churning about the matter and energy around us and we eventually decompose too.

Re: Argonne researchers posit way to locally circumvent Second Law of Thermodynamics

#63

Post by Florin_Andrei »

cndkxjsnf wrote: post #42
beagle3 wrote: post #40

Earlier quoted context omitted.

The second law of thermodynamics is as fundamental as the uncertainty principle: The former is a result from markov chains and information theory, the latter is a result from fourier analysis of conjugate variables. What would you consider a "fundamental physical law"?

Any law that's not based on a stochastic process, since stochastic processes can be gamed with a little bit of cleverness. If you don't believe me, just look at HFT.

You chose a really, really bad comparison there.

Re: Argonne researchers posit way to locally circumvent Second Law of Thermodynamics

#64

Post by protonfish »

clairity wrote: post #62
ThePhysicist wrote: post #34

The second law of thermodynamics isn't really a fundamental physical law, but rather a promise based on statistics that says "disorder will increase or stay constant in a closed physical system". That said, it's entirely possible for entropy to spontaneously decrease in a closed system, the probability of this happening is just astronomically small for typical macroscopic systems. Example: If you have a system consis…

aren't people (and all living organisms) the quintessential example of a local decrease in entropy that results in greater overall entropy? we are highly ordered groupings of matter but we're really great at churning about the matter and energy around us and we eventually decompose too.

No more so than the wall in the previous example that created a local decrease of entropy.

Re: Argonne researchers posit way to locally circumvent Second Law of Thermodynamics

#65

Post by btilly »

colanderman wrote: post #19

From the publication itself: > Note that in the discussed example the reservoir acts as some quantum analogue of the classical Maxwell demon. Namely, having been prepared in a special state, the reservoir is able to decrease the entropy of the system without the energy exchange with it, and can be referred to as a ‘quantum Maxwell demon’ […] In what was discussed above, an electron interaction with the quantum spin d…

I don't think so. There is no energy transmission involved at all. I suspect that there is some entropy transmission, but I didn't see an analysis of that, and the amount is negligible compared to what is already in the quantum mechanical system.

Of much greater surprise to me was the claim that an isolated quantum mechanical system neither gains nor loses entropy. I'm almost as astonished at this as I am at the fact that there are no chaotic quantum mechanical systems because quantum mechanical systems evolve linearly, while chaotic ones evolve exponentially.

If the latter astonishes you, I recommend reading https://michaelberryphysics.files.wordpress.com/2013/07/berr....

Re: Argonne researchers posit way to locally circumvent Second Law of Thermodynamics

#66

Post by btilly »

IBCNU wrote: post #47

Is not the 2nd Law of Thermodynamics always circumvented on Earth? We absorb more energy in the form of light from the sun than we emit.

The second law is not violated because the Earth is not a closed system.

Also to a very good approximation, we emit what we absorb. When averaged over a long period, that approximation gets better. (It has been somewhat worse over the last century though.)

Re: Argonne researchers posit way to locally circumvent Second Law of Thermodynamics

#68

Post by btilly »

paulmd wrote: post #39
api wrote: post #16

I recall having an idea at least a bit similar to this years ago when I was heavily studying evolutionary informatics. Some particularly avant garde types in that field have posited that the universe rather than having two constituents -- matter and energy -- has three primary first-order constituents. The third is information. Information is not merely an epiphenomena of matter and energy but a primary "thing." If t…

> Information is not merely an epiphenomena of matter and energy but a primary "thing." If that is the case then there should be an E=mc^2 type equation that relates matter to information and energy to information and all three should be interconvertible. I'm not sure I agree with this premise, but one thing I've been musing about is that there's probably an information-theoretic lower bound for the amount of energy…

There is a minimum amount of energy required to flip a bit. See https://en.wikipedia.org/wiki/Landauer%27s_principle for details.

This corresponds to a minimum amount of energy needed to transmit a given number of bits.

We are nowhere near this limit. However it is an upper bound that guarantees that Moore's Law can't possibly continue for classical computing to the end of this century.

(Part of the interest in quantum computing is that it has no theoretical upper limits at all. However this comes with some very weird restrictions.)

Re: Argonne researchers posit way to locally circumvent Second Law of Thermodynamics

#69

Post by bbctol »

clairity wrote: post #62
ThePhysicist wrote: post #34

The second law of thermodynamics isn't really a fundamental physical law, but rather a promise based on statistics that says "disorder will increase or stay constant in a closed physical system". That said, it's entirely possible for entropy to spontaneously decrease in a closed system, the probability of this happening is just astronomically small for typical macroscopic systems. Example: If you have a system consis…

aren't people (and all living organisms) the quintessential example of a local decrease in entropy that results in greater overall entropy? we are highly ordered groupings of matter but we're really great at churning about the matter and energy around us and we eventually decompose too.

Sure, but the above point was indicating that even a closed system is capable of decreasing in entropy, according to all other physical laws; it's just that the more complex the system is, the probability of the decrease declines rapidly to near zero.

Re: Argonne researchers posit way to locally circumvent Second Law of Thermodynamics

#70

Post by JumpCrisscross »

clairity wrote: post #62
ThePhysicist wrote: post #34

The second law of thermodynamics isn't really a fundamental physical law, but rather a promise based on statistics that says "disorder will increase or stay constant in a closed physical system". That said, it's entirely possible for entropy to spontaneously decrease in a closed system, the probability of this happening is just astronomically small for typical macroscopic systems. Example: If you have a system consis…

aren't people (and all living organisms) the quintessential example of a local decrease in entropy that results in greater overall entropy? we are highly ordered groupings of matter but we're really great at churning about the matter and energy around us and we eventually decompose too.

> aren't people (and all living organisms) the quintessential example of a local decrease in entropy that results in greater overall entropy

Complexity is orthogonal to entropy. The aforementioned barrier-separated box is high in entropy but simple. Upon lifting the barrier, a description of the gas front moving into the vacuum is enormously complex. It is also lower in entropy than the previous, barrier-separated state. Finally, when the gas is diffuse and entropy at its maximum, complexity dips back down.

Life is complex. Plants turn solar radiation into complex living structures; they also diffuse waste heat. Animals eat those plants, make more complex stuff, and generate more diffuse waste heat.

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