Argonne researchers posit way to locally circumvent Second Law of Thermodynamics

https://www.anl.gov/articles/argonne-researchers-posit-way-locally-circumvent-second-law-thermodynamics

by diggernet • 10 years ago

131 136 10 years ago

mabbo• 10 years ago

Someone smarter than me: why is this totally bullshit and will never work?

jrpt• 10 years ago

The second law of thermodynamics just follows from statistics and a large number of interacting particles. It's not actually inviolable as the article says. There are whole books written about far-from-equilibrium thermodynamics, and the fluctuation theorem quantifies the probability of entropy increasing https://en.wikipedia.org/wiki/Fluctuation_theorem

platz• 10 years ago

Right, the second law simply is a result of selecting a result from a probability distribution that increases entropy, but drawing from tails of the distribution aren't impossible, only highly improbable.

shoegumfoot• 10 years ago

Haven't read the paper, but it sounds like they just rediscovered the microcannonical ensemble (but for quantum mechanics). Probably works, probably hard to do anything interesting with it in the near to medium term.

yk• 10 years ago

Decreasing entropy locally is usually called a fridge, and I am currently betting my dinner that it is not bullshit. (I don't have the slightest idea what the article is actually talking about.)

digi_owl• 10 years ago

Could have sworn that one of the tricky things about that law was that while it may appear that you are decreasing entropy locally, you are just increasing it somewhere else, thus entropy still increased in aggregate.

hammock2• 10 years ago

Why do you have to swear? We (lifeforms) are living, breathing examples of that concept.

btilly6• 10 years ago

Ironically someone downvoted you for this comment. I guess that they didn't understand how exactly true your statement is.

In essence the entire biosphere is a giant heat engine, mainly fed off of the flow of energy from the Sun to Earth to outer space, and in some extreme environments fed by the radiation of heat out from the core of the Earth. Shut off those flows of energy, and the second law would shortly catch up to us and we'd all perish.

powrtoch• 10 years ago

Yeah. The impression I get from this article (which is pitifully short on specifics) is that they're going to exploit some of the seemingly-nonlocal properties of QM, like quantum teleportation.

So, a normal refrigerator decreases entropy in one region and increases it in another, but they're directly adjacent regions and the entropy (heat) is moving from one to another along a simple, everyday path (like a heat exhaust tube). It sounds like the researchers have proposed using some quantum-teleportation-like trick to have the heat show up in some unconnected region of space.

bryondowd• 10 years ago

Is it sad that my second thought reading that was of weaponization. Depending on how you project this energy, you could put it somewhere very much unwanted. Or the opposite, remove it from somewhere very much needed.

snowwrestler2• 10 years ago

Imagine location A experiences an entropy decrease Y. To compensate, location B experiences an entropy increase >Y, and thus the 2nd law of thermodynamics is upheld. Under typical conditions, those two locations must be directly connected. The biosphere of the Earth, which is a local decrease in entropy, receives insolation directly from the sun, and radiates directly into space.

The impression I get from the article is that the newsworthy idea here is that those two locations might not need to be directly connected. This would permit what looks like a perpetual motion machine. But overall the 2nd law would still hold because entropy is increasing somewhere.

Note: I'm not a physicist so don't take my word for this. Just conveying what I think I read.

powera• 10 years ago

"The authors are planning to work closely with a team of experimentalists to design a proof-of-concept system, they said." - Pardon if I'm mistaken, but this seems like a fancy way of saying they have no evidence at all so far.

lucideer2• 10 years ago

Like many theories... Peter Higgs et al had to wait ~50 years for evidence.

Filligree• 10 years ago

Quantum Mechanics is pretty damn solid. I expect they'll find their evidence, and figuring out that something is possible in QM is more than good enough reason to try it.

If that turns out to be false then QM will have been disproven, which is even bigger news!

lucideer2• 10 years ago

"Although the violation is only on the local scale, the implications are far-reaching," Vinokur said. "This provides us a platform for the practical realization of a quantum Maxwell's demon, which could make possible a local quantum perpetual motion machine."
For example, he said, the principle could be designed into a "refrigerator" which could be cooled remotely — that is, the energy expended to cool it could take place anywhere.

Perhaps there's another definition, but as far as I'm aware, a PPM has net negative/zero energy input from anywhere, be it local or remote.

That said, apart from hyperbolic misapplication of terminology (not a PPM, no circumventing Second Law), this does sound like interesting research.

azurelogic• 10 years ago

Countdown to a sci-fi movie where this idea is only half understood and the "proof of concept" device opens a portal to hell, where we meet the real Maxwell's demon...

Now that I've typed this, I want to see it happen.

pizza• 10 years ago

Use a recurrent neural network to generate said script!

theandrewbailey• 10 years ago

If so, one can't get into or out of hell unless you're going this fast.

pbnjay• 10 years ago

88mph of course...

cableshaft• 10 years ago

Wasn't that the plotline in the most recent Doom game?

eli_gottlieb4• 10 years ago

Several Doom games, and also Half-Life. Ripping a hole into Hell for travel purposes has been done in Doom, the movie Event Horizon, and the tabletop gaming franchise Warhammer 40K.

Which goes to show what a terrible idea this all is ;-).

lawless123• 10 years ago

And the portal is in some guys fridge.

tpeo2• 10 years ago

"There is no Dana, only Zuul."

mistercow• 10 years ago

Wait is this just turning into Ghost Busters?

highfestiva2• 10 years ago

Starts as a local sci-fi movie, heat-ends as a cosmological documentary.

oriel• 10 years ago

Narrated by Neil deGrasse Tyson

davesque• 10 years ago

I feel like Event Horizon was this in one form or another.

ridgeguy• 10 years ago

Charles Stross in his Laundry Files series may have pioneered that path (although no movies that I know of).

Do the wrong transform in, say, a Hilbert space and something quite horrible may come after you.

api• 10 years ago

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 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. It would then further follow that energy can be converted into information and vice versa in the same way that matter can.

I then imagined a Dyson swarm of solar power satellites that produce a data stream encoding the energy they collect. This stream can be subscribed to and decoded to reconstitute this energy remotely. To globally conserve energy there would have to be a two-way aspect to this -- I imagined the receiver of energy transmitting "challenges" to the swarm that are then "solved" to yield energy stored in the form of the solution. The receiver then receives these solutions and executes them to generate what in effect would look like local perpetual motion. (But in reality energy is still being conserved.) It would look like a cryptographic hashcash-style challenge-response system with proof of work, but the energy input of the POW function can be reversibly extracted elsewhere.

If such a thing were possible and sufficiently efficient and could function in the presence of high latency, this could power a starship among many other things. If it were latency-tolerant it might also be a way to store energy. Save your laptop's power to its hard drive.

It reminds me a little bit of the "telematter stream" propulsion system from Peter Watts' Blindsight.

eli_gottlieb4• 10 years ago

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."

Is that really so avant-garde? It seems a bit weird to claim that thermodynamics and the arrow of time are epiphenomena when we can measure the relevant quantities experimentally. The more avant-garde thing seems to be the kinds of papers where they claim space-time or gravity are somehow emergent from entropy/information.

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.

Uhh, why? Even the more exotic physics-of-information work seems to end up equating entropy with space-time or something like that: mass-energy would bend space-time-entropy, but wouldn't be convertible into it.

Admittedly, this is all way above my head.

logfromblammo• 10 years ago

If you could figure out how to remotely power a space habitat with nothing but downloaded prawn streams and lolcats, you, good sir, will end up ruling the galaxy, whether you want to or not.

If useful quantum information-to-energy conversion requires an observer, you will also solve the planet's unemployment problem.

paulmd• 10 years ago

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 it takes to transmit a given quantity of data a given distance. You can pick different points along a curve (higher bandwidth/higher frequency signals need higher power to produce a given SNR, and lower-bandwidth/lower-frequency signals can produce the same SNR at a lower power) but there is some asymptotic energy limit there that you cannot beat unless you have an infinitely sensitive receiver.

Anyway, what I'm going for here is that your unifying theorem there would probably be Shannon-Hartley, since that deals with the transfer (derivative) of information. The "noise" is whatever natural equilibrium opposes the transformation process, and your SNR dB is the equivalent of the rate constant in chemistry.

It's all fairly useless without some idea of how we convert hashes back into energy of course. Without that, there is insufficient data for a meaningful answer.

btilly6• 10 years ago

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.)

colanderman• 10 years ago

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 does not induce any correlations between the electron and the spin and, therefore, no classical correlations are present. Hence an important distinction between how do quantum and classical Maxwell’s demons operate.

So, it sounds like the "refrigerator-at-a-distance" (and thus energy transmission, when combined with a heat engine) actually (1) is more of a battery, and (2) doesn't interact with classical systems.

Is my reading correct?

btilly6• 10 years ago

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....

pdonis3• 10 years ago

Of much greater surprise to me was the claim that an isolated quantum mechanical system neither gains nor loses entropy.

Why is this surprising? It's a simple consequence of unitarity.

ivan_gammel• 10 years ago

The best thing with local and short-term effects is that eventually someone finds the way to extend the space and time boundaries a bit, then a bit more and then we are talking about astronomical scale.

Can be a nice story plot for a sci-fi book, in which science finds the way to defer the rise of enthropy to some almost infinitely distant moment in future (that end of time, we've always being expecting) and move the boundaries of locality to the observable universe. What a world that would be.

ThePhysicist3• 10 years ago

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 consisting of two compartments that are separated by a wall, where one of the compartments contains N particles. The system has low entropy because all the particles are on one side of it. Now, if you remove the barrier between the two compartments, particles will distribute evenly on both sides, increasing the entropy of the system. If we assume that the position of the particles is random, the probability of finding all of them on one side of the system is (1/2)^N, which quickly converges to zero for most macroscopic systems, which often contain > 10^23 particles.

beagle35• 10 years ago

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"?

cndkxjsnf• 10 years ago

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.

greydius• 10 years ago

Nature is under no obligation to comply with mathematical analysis.

tedsanders• 10 years ago

Would you mind sharing a link to a proof of the second law using Markov chains and information theory? I'd like to learn more about this approach.

I'm surprised that Markov chains would be involved when the laws of physics are deterministic.

The Poincare recurrence theorem has always suggested to me that the second law is not as fundamental as other laws. For a finite system with finite phase space, the state of a system will traverse closed loops, repeating forever with no steady increase or decrease in entropy. (Edit: to be clear, I'm not claiming that what I just described is the Poincare recurrence theorem or that it applies to our universe. But it is worth considering systems where the second law doesn't apply and trying to figure out how and if they differ critically from reality.)

https://en.wikipedia.org/wiki/Poincar%C3%A9_recurrence_theor...

Not that my background is worth anything, but just so you know where I'm coming from, I have a PhD in physics, spent years thinking about the entropy of computation, and wrote parts of the Wikipedia entry on Maxwell's demon. I think much of the disagreement over entropy and the second law comes from how we frame the problem.

klank• 10 years ago

I believe a distinction could be made around the second law of thermodynamics being emergent rather than, well, fundamental.

Put another way: the second law of thermodynamics is not required to fully describe a universe that acts like ours appears to. It will "take care of itself" based on more fundamental descriptions of matter and its interactions.

I'm also comfortable with what appears to be fundamental today no longer being fundamental tomorrow.

dahart2• 10 years ago

This list of what makes a physical law is a pretty good start: https://en.m.wikipedia.org/wiki/Physical_law#Description

Florin_Andrei3• 10 years ago

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.

I don't think enumerating the pedigree of a law gives it the seal of approval of validity. Newtonian physics also has pretty solid pedigree, and yet breaks down in relativistic conditions.

Please note I do not disagree with your conclusion, only with the way you present it.

goatlover• 10 years ago

A. One that doesn't derive from any other laws.

B. Was around at the beginning or prior to the big bang, as opposed to being the result of conditions early on.

C. What other laws, forces, constants, etc derive from.

wyager3• 10 years ago

The uncertainty principle is an absolute and inviolable consequence of pure mathematics; the second law of thermodynamics just makes predictions that are "very very overwhelmingly likely". The probability of the application of the uncertainty principle producing an incorrect prediction (internal to the theory) is zero, whereas the probability of the application of the second law producing an incorrect prediction (again internal to the theory) is non-zero. There is an infinity of difference between the internal "absoluteness" of these theories.

The probability of either theory producing an incorrect prediction external to the theory is much higher, and will be about the same for each theory. That is, it's more likely we're wrong about all of physics than that the second law makes a bad prediction in a bulk system.

Explanation of "internal" vs "external" probability: http://lesswrong.com/lw/3be/confidence_levels_inside_and_out...

dozzie• 10 years ago

After reading other posters, I believe the difference is similar to how terms "axiom" and "theory" function in mathematics.

clairity• 10 years ago

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.

protonfish• 10 years ago

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

bbctol• 10 years ago

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.

JumpCrisscross• 10 years ago

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.

ThePhysicist3• 10 years ago

Yes absolutely! Life is actually a way to increase entropy as it harnesses chemical energy in systems that otherwise wouldn't be able to reach a lower energy state by themselves.

jrapdx3• 10 years ago

A living organism is of course a noble endeavor standing against the tide of entropy. But it can do so only with significant influx of energy extracted from its external environment. The cost of constructing such an elaborate order of matter is paid by disorder elsewhere.

As we know, the living stance can be maintained for only a relatively short time, after which it rapidly decomposes to background entropy.

Interesting to speculate, as living beings we are chock full of "micro-environments", there could be exceptions to the laws of nature as we've understood them that could account for certain mysteries of biological nature.

mehwoot• 10 years ago

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

Yes, but that's not what the person you replied to was saying. They were pointing out that there can be a global, absolute decrease in entropy, it's just statistically very unlikely.

rascalpenguin• 10 years ago

This is very true, and is the case with many 'laws'. Another example is with centre of masses: Take a hollow sphere, clearly the c.o.m. should be in the very middle, yet an object placed inside has not force whatsoever on it so it isn't attracted to the c.o.m. and the idea breaks down (NB objects outside are attracted predictably).

This is because this idea is purely a tool to make calculations of large groups of particles as easy as one, but it does break down occasionally.

xenadu022• 10 years ago

I don't think that's true. An object would be attracted to the inner surface of the sphere because that's where the mass actually is. The shape you're describing doesn't have a center of mass the way we traditionally think of it.

dahart2• 10 years ago

Which law are you thinking of? There isn't a physical law I'm aware of that claims gravitational attraction toward a center of mass, you might be conflating several laws or thinking of an approximation rule that was never intended to cover one object inside or even near another.

Newton's law of gravitation is stated in terms of a particle to particle relationship.

Center of Mass is the balance point of an object, and objects will always rotate around their center of mass unless constrained, but this doesn't relate to gravity.

You can approximate gravity at a distance from any object by using the object's center of mass, but that approximation breaks down when you're close to it.

Chinjut• 10 years ago

This argument that the Second Law is a simple logical consequence of basic probability always seems glib to me. Why would probability demand entropy increase as one extrapolates forward in time, but probability not similarly demand entropy increase as one extrapolates backwards in time? In other words, what of Loschmidt's paradox (https://en.wikipedia.org/wiki/Loschmidt%27s_paradox)?

ilyagr• 10 years ago

There fact that is not a consequence of statistics is that we observe the universe to not be in the state of maximal entropy. That is sufficient to explain asymmetry of time, I think. The mystery is -- why wasn't the universe in a state of maximal entropy at time 0?

nabla92• 10 years ago

Universe started from low-entropy state. From the big bang, there is nowhere go but downhill.

In a microscopic level the physics can be time-symmetric (it seems not to be the case, there are T-symmetry violations), but macroscopically universe had higher entropy in the past (cosmological arrow of time)

edit: CPT-symmetry -> T-symmetry .

xenadu022• 10 years ago

That's one of the fundamental questions of physics. Hawking's Cambridge lectures audiobook explicitly cover the topic of what's up with the second law being statistical, why the arrow of time is apparently directional, and possible explanations for how you can answer those questions and explain the existence of the universe without requiring a "cause" for the big bang.

maverick_iceman7• 10 years ago

You are right in that we need to assume that the universe started in an extremely small entropy state. This is basically the past hypothesis. (Which can be justified to some extent using anthropic principle and eternal inflation, however these two ideas are very controversial among physicists.)

Retric• 10 years ago

Look at every possible two particle collision. To simplify, consider one of the particles as the initial frame of refernce so you now just have impact angle, which is random.

Now play back time by looking at that particle's post collision path as the frame of reference and play time backwards. You will find a bias in input angles for these collisions.

meganvito2• 10 years ago

I am not sure but have a question, is the barrier a kind of potential implied in the system?

meganvito2• 10 years ago

Or say, just the particles are the "insiders" of the "established system", while the barrier not.

fryguy• 10 years ago

Doesn't evaporative cooling work against the second law somehow? There is a system with some average temperature, and spontaneously enough entropy is created to cause some of the liquid to reach boiling temperature and leave the system, which decreases the average temperature of the liquid.

rubidium• 10 years ago

"closed physical system" being the operative word.

Mass and energy is leaving, thus the average temp decreases but so does the particle count.

mrcactu5• 10 years ago

I don't see what the big deal is. Let's try the ideal gas. For starters temperature ∝ Kinetic energy

We have two rooms. One were molecules all travel at speed A and other room molecules travel at speed B and we open a small window.

Eventually, over a long period of time the temerature in both rooms will settle at a temperature between that of B and of A.

Let's try to formule this mathematically. This is something like the mean value theorem in calculus that f'(C)(B-A) = f(B) - f(A) for some intermediate value C. And here are function f(C) is the equilibrium temperature.

In statistical mechanics we imagine we could count the number of particles -- 10^23 or 10^25 -- something very large. And some fraction M travel at speed A and N-M of them travel at speed B. And we count the probabilities of various mixtures occurring.

Feynman Lectures on Computation is a great book https://www.amazon.com/Feynman-Lectures-Computation-Richard-...

keithlfrost• 10 years ago

arxiv preprint of original paper here: https://arxiv.org/abs/1407.4437

IBCNU• 10 years ago

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.

snowwrestler2• 10 years ago

We're currently absorbing very slightly more energy that we emit. We call it global warming. Other than that, output balances input.

The atmosphere is a heat reservoir, but just like a water reservoir behind a dam, that doesn't mean it's ever-rising. Energy flows in one side and out the other, but between the two there is room for life.

btilly6• 10 years ago

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.)

timnic• 10 years ago

There is a free PDF on the nature site, but the paper is also available on arxiv (https://arxiv.org/abs/1407.4437), the first version on the arxiv dates back to 2014. It's strange, but I find the arxiv version much more readable in terms of typesetting than the polished version in nature. Also there are additional appendices in the arxiv version.

GregBuchholz• 10 years ago

This article seems a little light on details, and the original paper (not behind a paywall!) is quite dense, but some of my favorite paper's on Maxwell's demon are:

http://www2.pitt.edu/~jdnorton/papers/ExorcistXIV/Exorcist1....

http://www2.pitt.edu/~jdnorton/papers/ExorcistXIV/Exorcist2....

...and to ease into things, an article by one of the authors:

"The Simplest Exorcism of Maxwell's Demon -- No Information Needed"

https://web.archive.org/web/20140309110028/http://www.pitt.e...

highfestiva2• 10 years ago

I just knew it! Soon it won't be that local after all. ;)

maxwellion• 10 years ago

if a small theoretical being sat at the door between the hot and cold rooms and only let through particles traveling at a certain speed. This theoretical imp is called "Maxwell's demon."

Maxwell's demon is considered a slight of hand because it requires energy to perform its task. But if a passive energy-free equivalent can be found with a novel quantum substrate then any liquid could be separated into hot and cold pools. I am highly sceptical of such a claim. The difference in temperature between these hypothetical pools would likely be too small to create any useful energy.

Argonne researchers posit way to locally circumvent Second Law of Thermodynamics

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