[HN Gopher] Making a 'sandwich' out of magnets and topological i...
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Making a 'sandwich' out of magnets and topological insulators
Author : taubek
Score : 28 points
Date : 2022-04-11 06:58 UTC (1 days ago)
(HTM) web link (www.nanotechnologyworld.org)
(TXT) w3m dump (www.nanotechnologyworld.org)
| babyshake wrote:
| It seems that magnets have some truly remarkable properties as
| applied within electric/energy applications. Do we have evidence
| that it is not possible to essentially bypass certain laws of
| thermodynamics in the presence of magnetic fields?
| kurthr wrote:
| They're just creating bandgaps magnetically. I'm unsure exactly
| what the "breaking time reversability" refers to, but I don't
| think it looks like breaking any laws of thermo. Potentially,
| it could lead to superconductor-like effects near room
| temperature?
| pwr-electronics wrote:
| Nothing breaks the laws of thermodynamics, ever.
|
| I assume you're referring to how some popular science articles
| report things. That's just wordplay. Nothing is being bent,
| broken, or bypassed.
|
| Usually it just means they did something an ordinary
| homogeneous material couldn't do, for example. Which is
| genuinely interesting, even if it's not actually breaking
| physics.
| marginalia_nu wrote:
| With a generous interpretation, they can be said to break
| classical thermodynamics, since they quantum physics onto the
| table, most notably magnets can have negative temperature
| according to the statistical definition. Nothing that breaks
| physics at large, but would probably cause Ludwig Boltzmann a
| mild headache if he heard about it.
|
| It's still not going to allow you to make perpetual motion
| machines, though.
| pwr-electronics wrote:
| Why would you use a classical model to describe a quantum
| system? That's the kind of wordplay that those articles do,
| and almost identical to my example about materials. It's
| entertaining, but meaningless.
| marginalia_nu wrote:
| Well in this case you absolutely can, the results just
| seem counter to our intuition about temperature. Negative
| temperature is a meaningful description of these types of
| systems.
| pwr-electronics wrote:
| I'm trying to explain how articles often conflate
| "intuition" with "breaking physics", and you're making
| your argument by conflating them. We're having different
| conversations.
| marginalia_nu wrote:
| Where have I said anything about any of this breaking
| physics, other than repeatedly clarifying that it
| doesn't...?
| pwr-electronics wrote:
| > With a generous interpretation, they can be said to
| break classical thermodynamics
|
| https://news.ycombinator.com/item?id=31008263
| marginalia_nu wrote:
| Operative word being _classical_. Quantum physics breaks
| classical physics. Stopped being controversial about a
| hundred years ago.
|
| Thw very same comment specifically states that physics
| itself is not broken.
| pwr-electronics wrote:
| Ok, so you're confirming that you're doing exactly what I
| said popular science articles often do.
| marginalia_nu wrote:
| No I am not. Breaking classical physics is not breaking
| physics.
| zasdffaa wrote:
| > Do we have evidence that it is not possible to..
|
| No, I don't think so, it's just that no-one's ever been able to
| construct a perpetual motion machine, so that inability is
| codified into a presumption that energy can't be created out of
| nothing (for example). That is an axiom AKA a law of
| thermodynamics.
|
| I guess there's no possible proof of it but feel free to try
| making your own PMM - you'll make a fortune if you succeed!
| kurthr wrote:
| The original article:
|
| https://onlinelibrary.wiley.com/doi/10.1002/adma.202107520
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