
Nanoparticle Temporarily Violates the Second Law of Thermodynamics - srikar
http://scitechdaily.com/nanoparticle-temporarily-violates-second-law-thermodynamics/
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infinity0
It's not "violating" that law if it's only temporary. "In the long run" is
part of the definition of that law.

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adlpz
Additionally, the second "law" of thermodynamics doesn't even make sense at
those scales. It pretty much just shows that, in a given (isolated) system,
there are _way more_ "unordered" possible states (degenerate) than "ordered"
states, and due to basic statistics, in the long run the system will progress
towards being in those more probable states.

If the system is simple enough, the probability of jumping to a less-
degenerate state is large enough, and eventually, will happen.

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tormeh
Exactly. The probability that shards will meld into a glass pane and water
will form a snowman is nonzero, but simply very low. There are no absolutes
here.

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logicchains
If the many worlds interpretation of waveform collapse is correct, it's
possible that there's actually a universe somewhere in which the entire arctic
is covered in such snowmen.

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lloeki
I can't find the reference to the giant marshmallow hypothesis, stating that
it perfectly probable (although possibly scarcely) that there exists a giant
marshmallow that formed somewhere in space out of sheer luck. Probably Terry
Pratchett or Douglas Adams.

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Confusion
That the 2nd law can be temporarily violated on nanometer scale is not news:
that was already experimentally demonstrated years ago. The interesting thing
in this publication is that they experimentally verified a certain theoretical
description of that phenomenon.

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ThePhysicist
Well the second law of thermodynamics really isn't a law of physics but of
probability, since it basically states that it is very improbable for a
macroscopic system to go from a state with more disorder to a state with less.
An example:

If you take a glass chamber that is partitioned by a removable wall and where
one side initially contains a given number N of non-interacting particles with
random velocities, whereas the other side is empty. When you remove the wall
between the two halves, the particles will start flying around freely in the
chamber and will distribute roughly equally in the two halves. Now, the
probability that they will again concentrate in only one of the halves of the
chamber decreases exponentially with their number (as 2^N), so for macroscopic
particle numbers (typically > 10^20) you would have to wait a VERY long time
for this to happen. For a small number of particles, or a single nanosphere
like in the article, it might well happen though.

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darkmighty
Well there's a little more physics to it, namely that biases towards certain
distributions are small -- i.e. that systems always have paths to a large
number of states. The laws of physics has to be such that they exhibit
asymptotic equipartition.

In your example, assuming that particles positions are iid over the entire
container generates the second law, but only because the dynamics of the
system allow such approximation -- imagine instead that particles liked to
almost irreversibly "stick together", then the system would converge to most
particles on a single side.

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ThePhysicist
Yeah that's true of course and why I assumed they are non-interacting. It's of
course a gross simplification of the real theory but it explains quite well
why entropy increases in a closed system and as an explanation is not
conceptually wrong.

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interstitial
When it comes to the 2nd Law of Thermodynamics, internet discussions are like
the old biased coin toss: "Heads the 2nd law is true, Tails the 2nd law is not
not true". I wish Karl Popper was still around.

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mbrutsch
> However, when we zoom into the microscopic world of atoms and molecules,
> this law softens up and _looses_ its absolute strictness.

Hard to take a science article seriously when they write like an 8th grader.

