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Nobel Prize In Physics For Bose-Einstein Condensate
LMCBoy writes "The Royal Swedish Academy of Sciences announced the 2001 Nobel Prize in Physics today. The award went to scientists who managed to construct a Bose-Einstein condensate from Rubidium and Sodium atoms. The process involves cooling the atoms to about 20 nanoKelvin. From the press release: 'A laser beam differs from the light from an ordinary light bulb in several ways. In the laser the light particles all have the same energy and oscillate together. To cause matter also to behave in this controlled way has long been a challenge for researchers. This year's Nobel Laureates have succeeded - they have caused atoms to "sing in unison" - thus discovering a new state of matter, the Bose-Einstein condensate.'" This is the same reasearch that Hemos recently posted about.
Jeez... now I have yet another state and a crapload of equations to memorize. What's the enthalpy? The spontaneity?
We need a short form name. Solid, liquid, gas and Bose-Einstein condensate really just... doesn't work out that well in the naming scheme.
From the Physics department here at the University of Colorado, I consider myself lucky to work with folks like Dr. Weiman (one of the Nobel recipients) and others in the field, and congratulate all the Nobel winners for this year.
On that note, you can read all about Bose-Einstein Condensate and more at Physics 2000, our award-winning interactive journey through modern physics! The site is here:
http://www.colorado.edu/physics/2000
Our Bose-Einstein Condensate section is one of the most popular, check it out and learn more!
Ryan Bruels
Technical Consultant
Physics 2000
Center for Integrated Plasma Studies
University of Colorado, Boulder
"All your base are belong to this file I send in order to have your advice."
Rubidium and sodium have the intresting property that, when combined, they condense at around 35 kilojoules, very close to the famed Velhany constant.
However, it is also very difficult to find these two atoms in a pure form. The only good way to do it is to spin basic molecules containing these two elements through xeon gas within a 20 megagauss accellerator, of which there is only two in the world. Once you have them, it is very hard to keep them from combining with other elements again. You must immediatly cool them to around 3 Kelvin or you'll have to start all over again.
To actualy produce temperatures like 20 nano Kelvin, you can't use other materials (such as liquid nitrogen). The best way is to use two large magnets and a laser. If aligned properly, the magnets will actualy bend the laser around the atoms, producing a sort of barrier that will not allow energy in, but will allow it to escape. The magnets have the secondary effect of helping suck energy out of the material.
(Yes, I made all this up. I want to see how many people slashdotters flame me for all this BS when they haven't read this far down. Yes, I have karma to burn.)
Not a typewriter
Huh? A superconductor by definition already conducts current perfectly. There's no "best" superconductor in that sense, they're all the same (perfect). What people are researching now is high-temperature superconductors, which this is most definitively not (at 20 millikelvin).
main(c,r){for(r=32;r;) printf(++c>31?c=!r--,"\n":c<r?" ":~c&r?" `":" #");}
I thought the big deal about Bose-Einstein condensates was their indeterminate size. Since cooling matter down to nearly absolute zero halts motion, and since zero motion is a very measurable quantity, Heisenberg's uncertainty principle means that the actual location of the electrons becomes indeterminate, and therefore the size of the atomic shell grows bigger. Not sure what implications this fact has, though, but it's kinda neat. If anything ever were to be cooled to absolute zero, it would be of infinite size.
"Hardly used" will not fetch you a better price for your brain.
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--
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This Yahoo! News story about the Nobel prize includes discussion of potential applications.
Bose-Einstein matter was predicted decades ago. But the experimental cleverness to reach absolute zero and this state was only reached a few years ago. The prize is for this cleverness.
Second, not all othe the phenomena of this state were predicted by the theory, so new things were learned.
I listened to CNN sporadically today. Several times, I heard the CNN talking heads report on this Nobel award. Each time they only reported the names of the winners and that it was for "research in low temperature gases".
In each case, the 2nd news-reader (don't call these clowns reporters, please) turned to the 1st news-reader and made some lame comment about "boy is THAT way over my head (wink wink giggle)". They didn't mention the term "Bose-Einstein Condensate" nor did they attempt to explain WHY the BEC work would be worthy of a Nobel Prize.
Is it any wonder why the level of science illiteracy in the USA is so high?
IV
"These laws they're passing won't even compile anymore, let alone execute." - anon
Satyendranath Bose was a Indian Physicist.
Bosons (named after him) are particles that can be in the same quantum state.
The consequence of that is they can be in the same location.
While Fermions (such as electrons) cannot be in the same location (unless they are in Cooper pairs, which is how superconductors work, but I digress).
This is why electrons must exist in ever increasing shells around an atom -- they can never be in the same "location".
Einstein's contribution (at least I think this was his contribution), is to propose the following:
As well all know
To explain: If a particle is at location 'x', think of a Gaussian function centered at 'x', where the height of the function determines the probability that the particle is at that location.
A particle that is very well localized is traveling very fast, and vise versa.
And as the particle slows, the particle is less well localized, and it's wave function (that Gaussian) widens.
As Bosons (of the same type, say Rubidium atoms) cool, they slow down.
As they slow down, their wave functions expand.
At some point, their wave functions will overlap.
Now here is the cool bit. The atoms are in different quantum states and different internal energy levels to start with, but as soon as their wave functions overlap enough, they ALL immediately drop down to their ground state (which is the same for all of them), and you can no longer distinguish which atom is which!
The analogy would be to imagine an orchestra.
They are all tuning their instruments, but because they are all moving very fast, they cannot hear each other, and all the instruments are (or can be) in a slightly different tune.
When they all slow down (in the same room), they can hear each other, and suddenly they all become in tune with each other.
Not a very good analogy, I know.
Oh! I almost forgot. To cool the sample down to 20 nanoKelvin(?), this is what they do:
Of course once the condensate forms you can't measure it, b/c as soon as you try the damn thing evaporates!
So you have to observe it using other means....
"You have the option of insanity. I do not. And that makes me crazy!" - Brian to Angela, My So-Called Life