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Scientists Create New Form of Matter
soren100 writes "Yahoo News has a story about scientists creating a sixth form of matter. They are calling their new state of matter a 'fermionic condensate.' Somehow they got potassium atoms to form pairs similar to the 'Cooper pairs' that make superconducting possible. Maybe any quantum physicists around can tell us more about this, but it certainly sounds pretty revolutionary. The scientists are predicting that this will lead to 'room temperature solid' superconductors, which in turn will enable us to have better electricity generators, more efficient electric motors, and (our favorite) cheaper maglev trains."
"The new matter form is called a fermionic condensate and it is the sixth known form of matter -- after gases, solids, liquids, plasma and a Bose-Einstein condensate, created only in 1995." Come on people, RTFA already... :)
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Deborah Jin the team leader gives more of an idea of her work in this article. http://physicsweb.org/article/world/15/4/7
If you want the actual paper, and have access to the journal, it's published on the online version of Physics Review Letters Phys. Rev. Lett. 92, 040403 (2004)
abstract here for those with access.
I think this is possibly a big step towards room temperature superconductivity. The point is that in normal (even high Tc) superconductors, the forces between the cooper pairs are rather weak, hence the need to cool to at least 70K or so to get the effect. In this fermionic stuff, the force is a little stronger (at least, this is claimed in the article). Thus it may be possible to design a material which uses the same principle as the fermionic gas but in the form of a solid material at say 300K (just as high Tc superconductors are essentially solid B-E condensates, more or less).
BTW, I'm a cosmologist, not a condensed matter person, so I could be talking out of my arse.
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Apparently, what these guys did was closely related to forming Cooper pairs. When they found out other things related to this, we might be able to understand how to create these pairs at +25C. Right now one of the requirements seems to be to cool down the fermions, but if we find a way around...
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The article seems to highly stress the practical application of this new form of matter.
That is to say the least. It talks about superconductors for maglev trains etc. but in reality the new form of matter is a small blob of gas hanging trapped by lasers in a vacuum chamber. The only connection is that these studies may help us develop better theories about how superconductors work. (The current theories on high-temp superconductors are quite weak). A less popular introduction to Jins work is here, but it's not quite recent.
What are the safety and health issues involved in using this in 'practical applications'?
None. There are no practical applications yet, and when you look at the experiment it's just a submillimeter blob of potassium. The moment someone disturbs the experiment it will disintegrate and fill the vacuum chamber with very dilute potassium gas. Potassium can be dangerous, but there's a thousand times more in the bin they take it from, and I'm not worried about that at all.
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I've seen lots of posts saying "this has nothing to do with room temperature superconductors, but really cold gasses!" and whatnot.
The point is that the pairing formation of these fermions is potentially related to the Cooper pairing in electrons (also fermions). While it obviously isn't going to lead directly to a high temperature superconductor, the better we understand the mechanism IN GENERAL, the easier it will be for materials scientists and other condensed matter physicists to start figuring out how to get the critical temperature of REGULAR, SOLID superconductors up.
In that regard, this is big news.
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If one has a spin of +1/2 and the other has a spin of -1/2 then the composite "particle" will have a total spin of 0
This part is bogus, spin addition is more complicated than that. Whether you get a spin 0, 1/2 or 1 composite particle depends on the proper superposition of pair states. You can get an integer spin particle by combining two half-integer spin particles.
WRT the article, I don't see why they talk about having created a new state of matter. This is wrong, a claim only made up to attract attention. Superfluid Helium II is a Bose-Einstein-condensate of Helium 3, which has a half-integer spin -- exactly the same thing. There is one interesting difference, though: they managed to pick fairly heavy atoms, Potassium is much heavier than Helium.
Disclaimer: I'm a graduate student in physics.
"Only one fermion of a given type is allowed to be in a specific quantum state. A quantum state is a discrete level that can be labeled. The labeling gives information about the spatial characteristics (e.g. the orbit) and the spin of the particle. Two electrons can exist in the same quantum orbital, but only if they have different spin states. No two electrons of the same spin can occupy the same orbital state. "
That's why this is interesting.
yeah, I've got a degree in it. But engineering pays better.
Just google for "Pauli Exclusion Principle" and Fermion.
"Reality is that which, when you stop believing in it, it doesn't go away." - Philip K. Dick
I'll let Weimann (researcher at JILA, Joint Institute for Laboratory Astrophysics, his group was the first to create a BEC) do my talking for me since I only have an overview understanding of the topic:
"Although superfluid helium exists in conditions much warmer than the Bose-Einstein condensate that the Colorado researchers made, it is widely considered a Bose-Einstein condensate, even though it is in a very different sort of system than Einstein was talking about."[1]
Additionally in a Bose condensed gas strong interactions in the fluid state are eliminated making the system easier to understand and measure its properties.[2, 3]
So while it may be arguable whether its a new state of matter, based on how different the state is from a superfluid state, it is important because it makes the study of these systems in detail possible by eliminating many confounding interactions.[2]
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