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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.
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."
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?" `":" #");}
This Yahoo! News story about the Nobel prize includes discussion of potential applications.
Bzzt. At near absolute zero you approach what is called "zero-point motion". Quantum mechanical oscillators still vibrate at their lowest energy level (their energy being (1/2)*h*(frequency)). So even at absolute zero you don't have electrons flying all over the place. (Actually, room temperature is virtually absolute zero on an electronic basis anyway -- most electronic excited states are effectively in the thousands of kelvin).
Religion is the opiate of the masses. The wealthy smoke the real stuff.
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