Maxwell's demon extracts work from quantum measurement

July 10, 2017 by Lisa Zyga feature
The new Maxwell’s demon extracts work from a system by making a quantum measurement. Credit: Elouard et al. ©2017 American Physical Society

(Phys.org)—Physicists have proposed a new type of Maxwell's demon—the hypothetical agent that extracts work from a system by decreasing the system's entropy—in which the demon can extract work just by making a measurement, by taking advantage of quantum fluctuations and quantum superposition.

The team of Alexia Auffèves at CNRS and Université Grenoble Alpes have published a paper on the new Maxwell's demon in a recent issue of Physical Review Letters.

"In the classical world, thermodynamics teaches us how to extract energy from thermal fluctuations induced on a large system (such as a gas or water) by coupling it to a hot source," Auffèves told Phys.org. "In the quantum world, the systems are small, and they can fluctuate—even if they are not hot, but simply because they are measured. In our paper, we show that it is possible to extract energy from these genuinely quantum fluctuations, induced by quantum measurement."

In the years since James Clerk Maxwell proposed the first demon around 1870, many other versions have been theoretically and experimentally investigated. Most recently, physicists have begun investigating Maxwell's demons that operate in the , which could one day have implications for .

Most quantum versions of the demon have a couple things in common: They are thermally driven by a heat bath, and the demon makes measurements to extract information only. The measurements do not actually extract any work, but rather the information gained by the measurements allows the demon to act on the system so that energy is always extracted from the cycle.

The new Maxwell's demon differs from previous versions in that there is no heat bath—the demon is not thermally driven, but measurement-driven. Also, the measurements have multiple purposes: They not only extract information about the state of the system, but they are also the "fuel" for extracting work from the system. This is because, when the demon performs a measurement on a qubit in the proposed system, the measurement projects the qubit from one state into a superposition of states, which provides energy to the qubit simply due to the measurement process. In their paper, the physicists proposed an experiment in which projective quantum non-demolition measurements can be performed with light pulses repeated every 70 nanoseconds or so.

Since recent experiments have already demonstrated the possibility of performing measurements at such high frequencies, the physicists expect that the new Maxwell's demon could be readily implemented using existing technology. In the future, they also plan to investigate potential applications for quantum computing.

"This engine is a perfect proof of concept evidencing that quantum measurement has some energetic footprint," Auffèves said. "Now I would like to reverse the game and use this effect to estimate the energetic cost of quantum tasks, if they are performed in the presence of some measuring entity. This is the case in a quantum computer, which is continuously 'measured' by its surroundings. This effect is called decoherence and is the biggest enemy of computation. Our work provides tools to estimate the energy needed to counteract it."

Explore further: Physicists read Maxwell's Demon's mind

More information: Cyril Elouard et al. "Extracting Work from Quantum Measurement in Maxwell's Demon Engines." Physical Review Letters. DOI: 10.1103/PhysRevLett.118.260603, Also at arXiv:1702.01917 [quant-ph]

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Hyperfuzzy
1 / 5 (5) Jul 10, 2017
Who thinks like this? Everything is definitive. Why do we use results from random waves?
EmceeSquared
4.2 / 5 (5) Jul 10, 2017
Hyperfuzzy:
Who thinks like this? Everything is definitive. Why do we use results from random waves?


Why? Because *it works*. Quantum mechanics is an extremely effective theory, on which a myriad extremely effective techniques are based, which perform many clearly working things, precisely as predicted by the quantum mechanics used to design the techniques.

The real question is why do you constantly spam these discussions with inane, infantile whining that proves only that ambiguity makes you anxious. Yor whining doesn't seem to be making you feel any better. You're not convincing anyone of anything, the scientists can't even hear you, it just shows that you've got a psychiatric disorder.

OK, ambiguity scares you. Just keep it to yourself already. The facts reported in these pages are only going to demonstrate more effective applications of QM. And so they're just going to make you more nervous. Get lost already.
EmceeSquared
5 / 5 (3) Jul 11, 2017
If this experiment can produce data indicating the energy cost for its small QM measurement, it could start to define an overall minimum energy cost for the minimum QM measurement. Wouldn't that establish an energy:info equivalence principle, along the lines of Einstein's energy:mass equivalence E=mc^2?
nikola_milovic_378
Jul 11, 2017
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nikola_milovic_378
Jul 11, 2017
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Dingbone
Jul 11, 2017
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Dingbone
Jul 11, 2017
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Dingbone
Jul 11, 2017
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swordsman
1 / 5 (1) Jul 11, 2017
When an atom or molecule is excited by an electromagnetic field wave, it will exhibit some degree of mechanical motion. If the energy and wavelength are sufficient, a change in state can occur. If there is absorption of energy it produces a higher energy state, in which case there is energy absorption, not radiation. At higher excitation energies, there may be many changes in energy states. When the material is heated, random vibrations occurs, thus reducing the required optical energy. This is an interesting experiment that is not well explained in the article. What is a "quibit"? Is it simply one change in state of an atom? It is much more complex for a molecule. Many missing details.
EmceeSquared
4.2 / 5 (5) Jul 11, 2017
nikola_milovic_378:
Does the quantum have some mechanical property, so that we are examined by the law of mechanics?


Yes.

Why did you take the demon to determine and control the entrance to these states? ? It means that you believe in demons, and not in the Creators of everything existing.


No.

You don't know anything about quantum mechanics, or even the classical mechanics in which Maxwell described a "demon" to *illustrate* a physical principle with a *metaphor*. It is not a metaphysical "demon", as everyone who isn't crazy, lying or completely ignorant knows.

I don't care which you are: crazy, lying or completely ignorant. Probably all three, judging from your posts. Just stop posting your garbage in these discussions until you learn enough to post something worth reading. Spend your time improving your knowledge before you spend it polluting others. Get a different hobby.
EmceeSquared
3.7 / 5 (3) Jul 11, 2017
Dingbone:
But the notion of temperature may differ significantly from place to place. For example, if we constrain motion of electrons into narrow planes or wires (hole stripes within superconductor) then the temperature of electrons ACROSS the direction of these wires will become significantly lower (they prohibit the electrons in free motion) than ALONG them.


Please post the peer reviewed science articles that support your assertions that temperature behaves differently when constrained in a plane.

If you don't have any, the legitimate manner to discuss speculations is to ask a question, not to assert a fact without basis.

Your proposals are interesting, but if they're not supported by actual science then they're as interesting as any other science fiction.
Hyperfuzzy
3 / 5 (2) Jul 11, 2017
EMC^2, the point I get is no one knows what they are talking about. I say this with good intentions. If the mass thinks the earth is flat and you know a guy that has circumvented, ...

In other words our physics is related to what early man thought. Nothing is definitive. Temperature, then is a state of instability or stability. But is better defined as the spectrum and locality of disruptive wavelets emitted. Temperature? You mean Boltzmann, good try. None of it is particularly definitive.
EmceeSquared
4.3 / 5 (6) Jul 11, 2017
Hyperfuzzy:
no one knows what they are talking about.


Stop posting stuff we mere science-educated people cannot understand until you have your own research published in a peer-reviewed journal. This is a science site, and that's how science works. If you can't get your research published in a peer-reveiwed journal you're not going to get any of us to understand it. I say this with good intentions.

Invest your time getting it peer reviewed instead of wasting your time here where we just think it's annoying.
Hyperfuzzy
1 / 5 (1) Jul 11, 2017
Axiom: Charge, is never created or destroyed.
Lema: Only the center of the charge's field is moved by the field.
Lema: There exist nothing else.
Tautology: Charge is the Charge's field!

Maxwell, QED

Hyperfuzzy
1 / 5 (1) Jul 11, 2017
Hyperfuzzy:
no one knows what they are talking about.


Stop posting stuff we mere science-educated people cannot understand until you have your own research published in a peer-reviewed journal. This is a science site, and that's how science works. If you can't get your research published in a peer-reveiwed journal you're not going to get any of us to understand it. I say this with good intentions.

Invest your time getting it peer reviewed instead of wasting your time here where we just think it's annoying.

I'm reviewing you!
Dingbone
Jul 16, 2017
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Dingbone
Jul 16, 2017
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Dingbone
Jul 16, 2017
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Dingbone
Jul 16, 2017
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EmceeSquared
5 / 5 (2) Jul 16, 2017
Ding
We can just agree, that the genius which is two steps ahead with his explanations is perceived like crackpot.


Absolutely. Peer review is the only way we have to tell whether their claims are genius or crackpot. Why do you bother posting these long dissertation on some troll-infested science discussion site instead of getting published? The only people you're enlightening here are so naive or stupid that they're similarly enlightened by posts that quantum mechanics doesn't work even though it does. What they think of your work doesn't matter.

If you really think your work has merit, submit it to a peer reviewed journal. Take any feedback and apply it to your resubmission if necessary. That's how journals help you not just improve your work, but get scientists and the public to understand it. What they think of your work does matter.
Dingbone
Jul 16, 2017
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Dingbone
Jul 16, 2017
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Hyperfuzzy
1 / 5 (1) Jul 16, 2017
Why do you bother posting these long dissertation on some troll-infested science discussion site instead of getting published?
I think these ideas may be primarily useful pro practical experimenters with overunity, not for scientific researchers. We don't need more theoretical studies about how Maxwell demon can work in quantum mechanical systems - we need to research them practically and to focus to work, which has been already done (reportedly successfully) in this direction. We are running out of time in delaying the progress in this matter from both environmental, both geopolitical perspective. So I'm trying to address broader audience.

Pay attention, add a sort button with defined fields; users, rating, blah, blah

Remember, always place a gold star ahead of an article that makes sense, i.e. logic!
EmceeSquared
5 / 5 (3) Jul 16, 2017
No, you're getting both cases exactly backwards.

Dingbone:
Peer review is the only way we have to tell whether their claims are genius or crackpot
Of course not, for example the replication is way more reliable.


Without peer review, how does an experimenter choose which claims to try to replicate? How does a reader who isn't testing it know whether a given claim is worth the time to investigate? Peer review is *vetting*, so others can tell whether a claim is worth investing in. Whether investing time, money and reputation in replication, or just in reading a claim and thinking it through.

Claims are cheap, easy, and mostly wrong. The odds are against any one being right. Peer review increases those odds to be worth it.

It's essential for readers of claims to distinguish between worthless ones and worthy ones. Therefore they are essential to makers of claims so the worthy ones can be further investigated, eg. replicated, leaving the worthless ones behind.
EmceeSquared
5 / 5 (3) Jul 16, 2017
No, you're getting both cases exactly backwards.

Dingbone:
Peer review is the only way we have to tell whether their claims are genius or crackpot

[...]
Just in history of overunity and cold fusion findings the peer-review failed routinely and many times the articles even didn't pass the review but they were dismissed even before with silly editors, who did play the role of reviewers.


Peer review isn't perfect. Peers don't replicate. They're humans, so even with high knowledge and integrity they make mistakes. Science reputations are hard built, prohibitively costly to repair, so conservative in endorsing others' claims especially without replication - which is not part of peer review.

So yeah, some extraordinary claims with tiny evidence won't pass peer review even when they're correct. More evidence, or scaled down claims that the evidence supports more, will pass peer review.

BTW it's decades later and still no replication of cold fusion.
Dingbone
Jul 17, 2017
This comment has been removed by a moderator.
antialias_physorg
5 / 5 (1) Jul 17, 2017
Wouldn't that establish an energy:info equivalence principle,

There are a lot of parallels between energy and information (to the point where Shannon used the term 'entropy' when formulating information theory)
https://en.wikipe...ressions

And there have been attempts in the past to equate information and energy (Maxwell's Demon is exactly the thought experiment that was dreamed up for this). The minimum change of one bit of information is given as k*T*ln(2)

Energy and information are not entirely the same, though (no 'second law' in information theory). Also information is dependent on interaction with sender AND recipient. Energy itself is not (Energy is just the *ability* to do work not the work in itself)

...and, of course, information may not be quantized at all. QM is full of superpositions, continuous probabilities and partial measurements.
Hyperfuzzy
1 / 5 (1) Jul 17, 2017
Peer review is defined by a strict logic. Any peer review without concise fit to Formal Logic is not a review, it's a circle jerk!

In either, you may have whomever and whatever. Do you understand what you accept as a valid paper for publish, refs, etc., even Nobels?
Dingbone
Jul 17, 2017
This comment has been removed by a moderator.
EmceeSquared
5 / 5 (2) Jul 17, 2017
Dingbone:
Japan physicists replicated cold fusion with 100% reproducibility


Maybe they did, maybe they didn't. Without a peer-reviewed publication of their claims, it's impossible for anyone to tell the difference without that anyone personally replicating it. You didn't replicate it did you? I didn't. Because it's too expensive to waste time on the 99.9 44/100% of easily made claims that are just bunk.
EmceeSquared
3.7 / 5 (3) Jul 17, 2017
Dingbone:
BTW This thread isn't about peer-review neither cold fusion...


This thread *is* implicity about peer review, or rather the lack of it, as any *science discussion* must be. Cold fusion is an example of it.

Look, I just invested my time in explaining to you (once again), clearly and politely, why peer review is necessary to back assertions in a science discussion. You are actively ignoring its simple facts. Simple facts any reasonable person would already know or immediately recognize once reminded.

You don't care about science. You want to babble like a know it all, totally without regard to whether anyone accepts it, or if they do what their belief is worth (because they're totally unqualified to judge it). Instead of making your detailed assertions consistent with actual science by getting it peer-reviewed and published, you invent fallacies to denigrate peer review.

You're a public masturbator. Goodbye, weirdo.
Kron
not rated yet Jul 18, 2017
Try and stay on and refrain from pulling other commentators off topic EmceeSquared. Zephyr had some great input relevant to above article and you bated him into irrelevant nonsense. Quit trolling. I'm sure everyone here will do just fine without your explanations. Zephs scientific knowledge is quite evident and to anyone with two brain cells to rub together it is quite humorous to see you trying to teach him the scientific method. Two steps ahead of you is putting it lightly.
[Zephs] detailed assertions

What assertions are these exactly?
Look, I just invested my time

Invest your time elsewhere, please :)
Goodbye, weirdo.

If this were only true ;)
Dingbone
Jul 18, 2017
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Dingbone
Jul 18, 2017
This comment has been removed by a moderator.
EmceeSquared
5 / 5 (1) Jul 18, 2017
Dingbone:
Without a peer-reviewed publication of their claims, it's impossible for anyone to tell the difference without that anyone personally replicating it.


Of course, but there are many peer-reviewed evidence of their claims, already. See for example Appendix A, List 2 contains 153 documented peer reviewed excess heat observations.


Only 5 of those papers were published after a scientist published a peer-reviewed article showing a calibration error explains all their tiny heat generations, and those 5 (suspiciously) don't even mention their calibration method for review:
https://www.lenr-...ost62231

Also none of the claimed replications have themselves been reproduced. So cold fusion remains easy to claim, but neither reliably reproduced nor surviving rebuttal.
EmceeSquared
5 / 5 (1) Jul 18, 2017
Dingbone:
But the peer-review principle doesn't enforce anyone to replication, which is the actual criterion of scientific method - not peer-review. The contemporary society has no effective tools how to prohibit the scientists in ignorance of findings, which they don't have interest about - no matter how such finding could be contributory for tax payers, who are actually paying whole their fun. This is principial and still unsolved conflict of interests: the scientists are payed by publics but not enforced to actually serve the publics.


No, that's just a paranoid conspiracy theory totally ignorant of science. The scientist whose peer-reviewed 2005 article debunked all 148 prior peer-reviewed cold fusion articles pointed out that their (and their coworkers') safety depends on understanding the phenomenon:
https://www.lenr-...ost62114
EmceeSquared
3 / 5 (2) Jul 18, 2017
Dingbone:
Without a peer-reviewed publication of their claims, it's impossible for anyone to tell the difference without that anyone personally replicating it.


But the peer-review principle doesn't enforce anyone to replication, which is the actual criterion of scientific method - not peer-review.


Peer review is necessary, but not sufficient, to establish scientific facts. For example, Kirk Shanahan as I posted published a peer-reviewed paper demonstrating calibration error explained the tiny heat generation in the 148 peer-reviewed cold fusion papers published to that date. Without peer review, Shanahan would have been overwhelmed by claims *** LIKE YOURS *** posted with minimal cost or by mere obsessives, unable to target claims at least minimally vetted by legitimate scientists.

Peer review also isn't perfect, as 5 more papers got past peer review without including calibration data in the decade+ since Shanahan's paper. But that's only 3% of the previous.
EmceeSquared
5 / 5 (1) Jul 18, 2017
Dingbone:
During victorian era the laymen people were fascinated by perspectives of new findings and inventions in electromagnetism so that they did experiments on their own and they did buy various demonstrations toys. This inquisitive spirit completely waned from contemporary society: the people spend their time like the dilligent but still ignorant ants, who are interested about their own problems only.


Finally we see the romantic spirit of fact-proof mad pseudoscientists revealed. They crusade against the oppressive society's ignorance, heroic laymen. Also why Electric Universe pseudoscience is so popular among their fringe subculture: Gravity, fundamentally different from electromagnetism; it (AKA mass, AKA curved spacetime) replaced Victorian lone EM wolves with institutional researchers.

It's a culture rebelling against modernity, reverting to the 1800s, with all that implies for them. Complex modernity overwhelms them, so they deny its "conspiracies".
EmceeSquared
5 / 5 (1) Jul 18, 2017
Kron:
Try and stay on and refrain from pulling other commentators off topic EmceeSquared.


The topic is *science*. These pseudoscience assertions, that I specifically referred to yet you evidently can't track of, are not science. Insisting on peer review is keeping them on topic. You want pseudoscience, go to a pseudoscience blog. There are many of them.

I'm not trolling, I'm interested in legitimate discussion. Insisting on pseudoscience is not legitimate in a science site. Without peer review (and especially when attacking peer review), claims are not scientific, they're just claims.

All you're doing is proving there's an audience for public masturbators. But this science site isn't the place for that either.
Dingbone
Jul 18, 2017
This comment has been removed by a moderator.
EmceeSquared
5 / 5 (1) Jul 18, 2017
Dingbone:
Without peer review (and especially when attacking peer review), claims are not scientific, they're just claims
Well, exactly - I linked list of http://lenr-canr....fcol.pdf - and what I got? Just a claims and link to some anonymous forum. Your own criterion should apply here.


Look, I can go through the work to pull Shanahan's peer-reviewed paper from the forum I linked you to. But will you accept that it eliminates those 153 peer-reviewed papers as acceptable evidence for cold fusion? I bet not. If not, I'm not going to bother. Why should I?

That doesn't "make us even". It leaves you refusing to accept when peer review does its job, giving scientists a vetted collection of work to scientifically disprove if they can. It leaves me doing my due dilligence wading through your claims of support to find the scientific disproof of them. Not at all even.

Unless you accept when your proof is disproved. That's worth investing my time in.
Dingbone
Jul 18, 2017
This comment has been removed by a moderator.
Hyperfuzzy
not rated yet Jul 18, 2017
The excess heat results, the tritium and helium are indisputable.

This not the place to discuss nuclear! Is it?
Dingbone
Jul 18, 2017
This comment has been removed by a moderator.
EmceeSquared
5 / 5 (2) Jul 18, 2017
Dingbone:
The excess heat results, the tritium and helium are indisputable. That is to say, no one has ever disputed them. There are no published papers showing errors in the measurements of any mainstream paper, except Shanahan and Morrison, who didn't any cold fusion experiment themselves.


So your answer is "no". And you tried trolling me with "where's Shanahan's peer reviewed paper, it's just a claim" when you knew all along about Shanahan's peer reviewed paper. That is precisely why I didn't spend the time getting it for you: you'll never accept actual science that interferes with your fantasy.

Shanahan showed that the previous papers claimed extraordinary results that were easily explained by bad calibrations rather than by a novel and never reliably reproduced mechanism. He doesn't have to do an experiment to do so.

All you are doing is demonstrating how essential peer review is, even though not sufficient for proof. Which you ignore whenever convenient.
EmceeSquared
5 / 5 (1) Jul 18, 2017
Dingbone:
There are no published papers showing errors in the measurements of any mainstream paper, except Shanahan and Morrison


BTW, Marwan et al's *letter* to JEM was not peer reviewed. And though Shanahan's letter published in JEM responding to Marwan's *letter* wasn't peer reviewed either, Shanahan's was joined by many scientists in the field confirming Shanahan's letter. That's as close to peer review as *letters* in journals get, which Marwan et all don't even have.

Thanks for wasting my time tricking me into looking that up, even though you won't accept any reality of peer review. But at least the next time you or some other delusional public masturbator bring it up I'll be able to easily slap it down again.
Dingbone
Jul 18, 2017
This comment has been removed by a moderator.
EmceeSquared
not rated yet Jul 18, 2017
Dingbone:
I already said, that peer-review is necessary because without peer-review the scientists would cheat like crazy, therefore the peer-review is required as a criterion for paying the scientists in advance before their results will be finally accepted (outside the peer-review scrutiny).


OK, so peer review is necessary. So you agree to stop posting your own original research here until it's been published in a peer reviewed journal first. Because, as we agree, peer review is necessary, right?
Kron
not rated yet Jul 18, 2017
Stop engaging the troll Zeph. That shifting blame rhetoric he's pulling is just to get under your skin. What does he care if a paper is peer reviewed? He doesn't have the aptitude for academia. Quit trolling Emcee, get another hobby please.
EmceeSquared
not rated yet Jul 19, 2017
Kron:
Stop engaging the troll Zeph. That shifting blame rhetoric he's pulling is just to get under your skin. What does he care if a paper is peer reviewed? He doesn't have the aptitude for academia. Quit trolling Emcee, get another hobby please.


Why are you so scared that Dingbone has finally agreed that peer review is necessary? Because requiring peer review disqualifies your favorite pseudoscience? Because real trolls like you, who (as per the troll definition) aren't interested in discussion but merely disruption, can't tolerate being disqualified for pseudoscience?
Hyperfuzzy
not rated yet Jul 19, 2017
Kron:
Stop engaging the troll Zeph. That shifting blame rhetoric he's pulling is just to get under your skin. What does he care if a paper is peer reviewed? He doesn't have the aptitude for academia. Quit trolling Emcee, get another hobby please.


Why are you so scared that Dingbone has finally agreed that peer review is necessary? Because requiring peer review disqualifies your favorite pseudoscience? Because real trolls like you, who (as per the troll definition) aren't interested in discussion but merely disruption, can't tolerate being disqualified for pseudoscience?

Actually, a computer program is a better reviewer and researcher! No good without logic!

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