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New Superconductor Theory May Revolutionize Electrical Engineering
An anonymous reader writes "High-temperature superconductors exhibit a frustratingly varied catalog of odd behavior, such as electrons that arrange themselves into stripes or refuse to arrange themselves symmetrically around atoms. Now two physicists propose that such behaviors – and superconductivity itself – can all be traced to a single starting point, and they explain why there are so many variations. Most subatomic particles have a tiny magnetic field – a property physicists call 'spin' – and electrical resistance happens when the fields of electrons carrying current interact with those of surrounding atoms. Two electrons can join like two bar magnets, the north pole of one clamping to the south pole of the other, and this 'Cooper pair' is magnetically neutral and can move without resistance. Lee and Davis propose that this 'antiferromagnetic' interaction is the universal cause not only for superconductivity but also for all the observed intertwined ordering. They show how their 'unified' theory can predict the phenomena observed in copper-based, iron-based and so-called 'heavy fermion' materials."
I will go on the record as saying I am 100% in favor of superconductors. All you anti-supercondites can chomp it!
NAO!
Of course! It's so simple now!
#DeleteChrome
magnets...how do they work???
have you seen my sig? there are many others like it but none that are the same
Spin is an angular momentum, yes it does generates a magnetic momentum that gives origin to a field. But calling spin a field is like calling earth's angular momentum gravity.
to one of the BASIC test programs for my Commodore 64 that would fill the screen with random / and \ characters, resulting in a similar pattern. If only I'd made the connection to intertwined ordered phases earlier!
Mostly random stuff.
Does it predict any room temperature superconductors?
Does this theory predict that really high temperature (room temperature or higher) superconductors are possible, or that they are not? If it does, can it indicate anything about what sort of materials we should be trying to use to fabricate it?
File under 'M' for 'Manic ranting'
Would it kill them to link to the original paper? It's not even paywalled:
http://www.pnas.org/content/110/44/17623.full.pdf+html?sid=5925a7b2-3efe-4a21-99f9-0e448cd3a7cf
Maybe it could explain statene
Now there was a superconductor. Odd behaviour and all.
Per the article, statene isn't a superconductor.
"Although stanene and superconductors can both act like perfect conductors of electricity, Zhang emphasizes that stanene is not a superconductor. While the edges of stanene act as a highway for electrons, those electrons still encounter 'contact resistance' when they move between the stanene and normal conductors. In a superconductor, in contrast, electrons travel in pairs, a phenomenon that can eliminate contact resistance. In other words, a normal conductor essentially acts like a superconductor when it is placed in contact with a superconductor."
FWIW, this appears to be mostly first order theory that is able to exhibit the known interactions that are presumed to destabilize known forms of high-temp superconductivity. It isn't a revolutionary idea, many physicists presume that the interaction of the topology of the Fermi-surface are keys to understanding why some high-temp superconductors work and some do not, but I'm guessing these folks are one the first to show a way to generate most of the known interactions in most types of known high-temp superconductors (apparently other people have done this for copper-oxide HTSC) and hence why this is considered a "unified" theory.
The insight they appear to claim is there aren't certain configurations of Fermi-surfaces that generate interactions that destabilize HTSCs, but the key is in the energy regime of electron-electron interaction of the anti-ferromagnetic interaction itself. It's kind of like saying in the domain of the formation of these superconductivity inhibitors, it's too simplifying to consider energy regime of particle-field interaction (e.g., electron-pair vs Fermi-surface) but you must consider the energy regime of particle-particle interaction.
Like all things new, it may be a start, but on the other hand, it is still an untested theory (it's a theory crafted to exhibit known results). If it turns out to be predictive, maybe it might lead to something interesting.
"Ideally we would like to be able to tell the materials scientist to put elements X, Y and Z together," Lee said. "Unfortunately we can't do that yet."
It's not the funniest thing I've ever read around here, but it is actually a little funny.
Space game using normal deck of cards: http://BattleCards.org
Seems to me that there ought to be a corollary to Betteridge's law of headlines (A headline with a question mark can be answered by "no") for headlines with the word "may".
"Scientific advance X may achieve Y" can be read as "Will scientific advance X achieve Y?". To which the answer is "no", followed by "That's how researchers attempt to get more funding for X, a small advance of interest to those in the field but not exactly flying cars, by pretending it might lead to Y, which it almost certainly won't."
http://www.youtube.com/watch?v=yxBT1pfVAKQ
(Why was a poorly written press release linked instead of the actual paper?)
This paper shows how you can start with an extremely simple theory of electron interaction and build up to some very complicated, realistic superconducting behaviors. When varying the material properties of high temperature superconductors, you always see an antiferromagnetic material type near the superconducting material composition. For many years condensed matter physicists have suspected that this was more than a coincidence and that high temperature superconductors work because of finely tuned antiferromagnetic interactions between electrons. Although this paper simplifies electron interactions considerably (come on, we're physicists, simplification is what we do), it does fill in some of the larger holes in that theory and is an important step toward understanding the physics behind the phenomenological high temperature superconductivity models.
How's that MP3 collection going?
I considered switching to it but since it's a fairly new format I'm concerned about the longevity of it.
I'll stick to keeping my collection in RealAudio for now.
That is such a misused statement(s), there is very little chance you ever
hear of this again, not just this article but anything that's claiming to
be anything other than an interesting article.
Remember the glass bottles with a coating inside that made the very last
drop of ketchup/mayonnaise flow, ending waste? Never heard of it again.
Mouth wash that used once would completely eliminate tooth decay? Yep, dead story.
I'm not even taking the time to look for links you all know of some
"make this a better world" solution that never sees the day of light, let
alone another word.
Too bad China has the monopoly on rare earths.
They're not actually rare. China has a monopoly mainly by being a very cheap producer of something that requires a lot of messy processing to make; everyone else is happy to let them have a monopoly because it's expensive to do otherwise, not because they actually control all possible sources.
"Little does he know, but there is no 'I' in 'Idiot'!"
There are easily a half-dozen or so contenders but when I was a lad likely the two most common lies were "The check is in the mail." and "I'll pull out in time."
Magnets work by selective attraction, not to be confused with beer goggles. Look for the "This sign up." side.
Let me google that for you...
XML is like violence. If it doesn't solve your problem, you're not using enough of it. --AC
Get a login, earn some karma and do it yourself, you lazy git.
systemd is Roko's Basilisk.
Keep in mind this is not really a freely moving particle being measured, and is actually a bound electron(s) being measured multiple times as it orbits the same atom. And yes, the act of measuring the electron can make it jump to its neighbouring atom's nucleolus, but that would leave a positive void which some other electron would quickly find because of zero resistance of the substrate.
Stick them together this way (along their sides):
[N==S]
[S==N]
"Flame away, I wear asbestos underwear"