
Argonne researchers posit way to locally circumvent Second Law of Thermodynamics - diggernet
https://www.anl.gov/articles/argonne-researchers-posit-way-locally-circumvent-second-law-thermodynamics
======
ThePhysicist
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.

~~~
beagle3
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
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.

~~~
lawpoop
What is HFT?

~~~
nicolapede
High-Frequency Trading, I'd think.

------
azurelogic
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.

~~~
lawless123
And the portal is in some guys fridge.

~~~
tpeo
"There is no Dana, only Zuul."

------
colanderman
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?

~~~
btilly
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...](https://michaelberryphysics.files.wordpress.com/2013/07/berry337.pdf).

~~~
pdonis
_> 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.

~~~
btilly
It surprises me because the universe is an isolated quantum mechanical system
that certainly appears to be gaining entropy.

~~~
pdonis
The apparent contradiction here should not make you doubt the statement that
an isolated quantum system can't gain entropy. It should make you doubt the
statement that the universe, or at least the "universe" that appears to us to
be gaining entropy, is an isolated quantum mechanical system. In other words,
it should make you consider the possibility that we observe an apparent
entropy gain because we can only observe a portion of the universe, and that
portion is entangled with portions that we can't observe (and might never
observe given that the expansion of the universe is accelerating). We never
actually observe the pure state of the universe as a whole.

------
digi_owl
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.

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

~~~
btilly
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.

~~~
maxerickson
Shut off the flow of energy and the cold would catch up to us a long time
before the second law of thermodynamics.

(our frozen, desiccated corpses would probably retain their organization
_longer_ under such conditions)

~~~
tpeo
I'm no physicist, but isn't the cold a result of the second law? Or is the
second law a consequence of the dissipation of heat?

Also, is thermodynamic entropy applicable to organized matter?

~~~
maverick_iceman
It is applicable to _everything_.

------
maxwellion
> 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.

See also:

[https://en.wikipedia.org/wiki/Exergy](https://en.wikipedia.org/wiki/Exergy)

[https://en.wikipedia.org/wiki/Thermoelectric_generator](https://en.wikipedia.org/wiki/Thermoelectric_generator)

------
lucideer
> "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.

------
GregBuchholz
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/Exorcist1.pdf)

[http://www2.pitt.edu/~jdnorton/papers/ExorcistXIV/Exorcist2....](http://www2.pitt.edu/~jdnorton/papers/ExorcistXIV/Exorcist2.pdf)

...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...](https://web.archive.org/web/20140309110028/http://www.pitt.edu/~jdnorton/Goodies/exorcism_phase_vol/exorcism_phase_vol.html)

------
effie
It seems as though the authors are confusing Boltzmann's H-theorem and its
cousins expressed in more complicated formalisms with the Second law of
thermodynamics. That's a very common misconception, often resulting in
announces of apparently great discoveries, while the sober account would be
more akin to "we derived a theorem where this special expression, similar to
Boltzmann's H-function, does not behave as one would expect based on the
H-theorem, which in turn is proven to be valid only for a simplified model of
ideal gas in special condition." Not so interesting. Second law is an
experimental law that concerns macroscopic systems. So far, this law was not
shown to be violated based on any broadly accepted theory.

------
lubesGordi
So this article does the Maxwell Demon some injustice. There is a key point
about the demon that when he is 'sorting' the particles into two bulbs or
rooms, that the gate he is working on is frictionless. In this way, you can
can see that there is no energy entering the system, yet the entropy is
decreasing. Now, this is where things get interesting to me (please correct me
if I'm wrong here). What the demon is adding is information to the system. It
decreases entropy. Natural selection is a sort of maxwell demon in it's
selection process. I have a theory though that it all evens out. The more
complex/evolved the organism, the more entropy the organisms generate
themselves.

~~~
taneq
> There is a key point about the demon that when he is 'sorting' the particles
> into two bulbs or rooms, that the gate he is working on is frictionless.

Exactly. Maxwell's Demon is a magical construct. In reality, any active device
that sorts molecules into high and low energy bins would take power to run,
and would generate more heat (or other entropy) than it removed by doing the
sorting.

~~~
lubesGordi
While what you said is true, it sort of misses the point. The thought
experiment demonstrates that there is some quantity being added to a system
each time the demon opens or closes the gate, and that quantity is
information. Now we have a relationship between information and entropy.

Edit: I think you might be speaking to my point that in the end it evens out,
and that natural selection in turn does create entropy even as its generating
information.

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

~~~
jrpt
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](https://en.wikipedia.org/wiki/Fluctuation_theorem)

~~~
platz
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.

------
al2o3cr
A quick read of the paper shows it's mostly focused on systems with discrete
levels; IIRC there's already plenty of thermodynamic weirdness in those, like
"negative temperature" states in the Ising model and so forth. They touch on a
continuous system in the final section, but that also includes a system with a
finite upper bound to its energy (phonons). Wonder if that's related to the
potential for 2nd Law violations.

------
timnic
There is a free PDF on the nature site, but the paper is also available on
arxiv ([https://arxiv.org/abs/1407.4437](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.

------
crpatino
You lost me at "locally". Of course if you take a closed system A and make it
a subsistem of some bigger closed system B you are going to be able to
diminish entropy at A by increasing entropy even further at (B + !A).

My grandmother's freezer was doing this 50 years ago, and I am pretty sure the
engineers who designed it did not think their work was fundamental research in
any way or form.

------
jbmorgado
This doesn't actually violate the law. This just goes on to prove it.

The reduce the entropy locally but in the process of doing so, increase it
globally. It strictly follows the 2nd law of thermodynamics.

------
ivan_gammel
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.

------
pjdorrell
By "locally" I think they mean something like "entropy will decrease within
what looks like a closed system, and it might not be immediately obvious where
else in the universe the corresponding increase in entropy is occurring".

So not actually "free energy", but perhaps it could be used to stage a
convincing demo to potential investors.

------
mrcactu5
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-...](https://www.amazon.com/Feynman-Lectures-Computation-
Richard-P/dp/0738202967)

------
powera
"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.

~~~
Filligree
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!

------
keithlfrost
arxiv preprint of original paper here:
[https://arxiv.org/abs/1407.4437](https://arxiv.org/abs/1407.4437)

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

------
maverick_iceman
Original article[1].

[1]
[http://www.nature.com/articles/srep32815](http://www.nature.com/articles/srep32815)

------
IBCNU
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.

~~~
btilly
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.)

------
mirekrusin
I wonder if we're going to read titles like "Global warming solved? We're
going to send heat to Mars?".

------
gandolfinmyhead
Maxwell's demon is probably laughing his head off.

------
api
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.

~~~
paulmd
> 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.

~~~
btilly
There is a minimum amount of energy required to flip a bit. See
[https://en.wikipedia.org/wiki/Landauer%27s_principle](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.)

