Slashdot Mirror
The Fermionic Version of Bose-Einstein Condensates
Sargent1 writes "According to Science magazine's web page, a group of physicists at Duke University have managed to cool fermions to the point that they may be seeing superfluidity in a fermi gas. If they are seeing fermionic superfluidity, their work is to fermions what Bose-Einstein condensation (BEC) is to bosons, and the creation of BEC won some folks the Nobel prize in 2001. Beyond that, they've got the fermions interacting so strongly that they're a good analog of fermions in white dwarfs and neutron stars. This gives experimenters the chance to investigate neutron stars without having to have one parked out back in the lab."
Well thanks for making me feel like an utter retard. I have no idea what any of this means.
Best Windows Freeware
The ability to model white dwarfs, and neutron stars! He, he, he!
This is the kind of thing that got me into physics. LASERs, exotic astronomical objects, cool labs,and semi-mysterious doings.
It's enough to make a Vulcan giddy!
"Oh drat these computers, they're so naughty and so complex, I could pinch them." --Marvin the Martian
Now we're going to start seeing ads in the upcoming issues of "Evil Genius Monthly":
You have your evil lair, an arch enemy, and an earth destructo ray. You've even got your space platform and trained monkey contingent to help you escape to it in peril - but where are your minions? You need evil minions to do your bidding.
Introducing our latest product for your overlording pleasure: Ferminions(TM). More evil than evil itself, our Ferminions(TM) are developed in secret underground lairs using a secret process so secret that we don't even know it (patent pending). Buy a pack* today!
- Adam
* Ferminions only available in Evil-Purple jumpsuits. Do not fold, spindle or mutilate. No user-servicable parts inside. Bosons not included.
...the part where it says,
You cannot apply a technological solution to a sociological problem. (Edwards' Law)
"And how many supernovae, I wonder, really are industrial accidents?"
We all remember BECs, right? That's where you cool bosons down to the point that they are all in the exact same (lowest) energy state. This leads to interesting stuff, that's kind of important.
This is similar. The difference between Bosons and Fermions is that no two fermions can be in the exact same state. (The Pauli exclusion principle.) So you cool fermions down in a way similar to the way you cool Bosons down to get BEC, and instead of all the atoms being in the same state, they each take the lowest state that's not already occupied. This is very similar to what happens in semiconductors... you CAN understand this. They are basically using atoms to do the same thing that happens in semiconductors with electrons.
This is a very big deal, as this type of "degenerate fermi gas" is everywhere. From neutron stars to the center of Jupiter, this stuff shows up in theories all over the place.
with a bumper sticker that reads 'my other star is a giant'.
- undoware.ca
In a Bose Einstein Condensate, when some particle comes flying in fron the vacuum and smacks an atom in the condensate, they both go flying out. You have one less atom in your condensate now, but it's about the same temperature.
You can imagine the temperature of a Fermi Gas as the apparent neatness of an upside down pyramid of blocks. At high (room) temperatures, the blocks are all jumbling around in a mess. At zero temperature, they are perfectly fitting on top of each other, filling the energy levels of the trap.
Now a hot atom comes flying in from the vacuum and takes out a block in the middle. Now the whole thing above the hole is messed up! As the atoms shuffle around to fill up the hole, this is expressed as heating.
So the fact that thy have been able to cool these atoms is a testament to their experimental rigor, especially with their vacuum system.
Just thought I would offer some insight.
Muerte
Someone feel free to correct me if I err, but BECs count as a "really neat" concept due to the superposition of the constituent particles - they basically stop existing as distinct objects and form a quantum blur, with all kinds of interesting quantum properties not normally seen on such a relatively enormous scale.
Fermions cannot exist in such a state, so this seems more like cooling off an "ideal" gas - just an optimal packing problem, no more "neat" than the fact that, say, silicon below a certain temperature exists as a crystaline solid. Except they used fermions rather than silion atoms.