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Science

Nobel Prize In Physics For Bose-Einstein Condensate 201

Posted by timothy from the get-to-meet-the-king dept.
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.
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Nobel Prize In Physics For Bose-Einstein Condensate More

Nobel Prize In Physics For Bose-Einstein Condensate

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  • That Timothy! (Score:1, Informative)

    by Anonymous Coward
    He ought to take more credit! After all, he was the first [slashdot.org] to post a story on this topic. :-)

  • Ahh yes, masers (Score:1, Insightful)

    by ispq ( 301273 )
    They did the research on this several years ago. Nice to see them getting official recoginition.
    • That's usually the way it works. It takes several years for research to translate into Nobel recognition. I suspect it's partly -- even primarily -- because the committee wants to take sufficient time to ensure that the "discovery" isn't a dud (anyone remember cold fusion?).

      I mean, one can't exactly renege on a Nobel prize, now, can one?

    • These are not masers! (Score:3, Informative)

      by Drakula ( 222725 )
      A maser is Microwave Amplification by Stimulated Emission of Radiation and have nothing to do with Bose-Einstein condensates. You are probably thinking of so called "matter lasers" which are related. The B-E condensate is only a component of that.

      Particles that can all have the same EXACT state, in quantum mechanical terms, are called bosons. They fill and occupy available states in a certain way, described by a Bose distribution. An example of bosons are photons, or light, which can all be in the same state at the same time, hence making the maser and laser possible. Opposite to these are fermions, e.g. electrons, which cannot occupy the same state and are subject to Fermi-Dirac statistics.

      What makes B-E condensates cool, no pun intended, is through cooling and laser pumping all the atoms can be made to be in the exact state. This allows all kinds of neat things to happen. Such as the "matter laser" or the actual slowing down and stopping of light (I'm to lazy to look up the link but check out Scientific American's website).

      Pretty neat stuff.
      • Particles that can all have the same EXACT state, in quantum mechanical terms, are called. They fill and occupy available states in a certain way, described by a Bose distribution.

        Um, no. Bosons are (by definition) particles with integer spin (0, +1, -1, etc.).

        An example of bosons are photons, or light, which can all be in the same state at the same time, hence making the maser and laser possible.

        Umm, no. Photons, because the have no mass, are completely unable to form a Bose-Einstein condensate. In a laser, the photons are emitted with coherent phase. This is not at all the same as being in the same quantum-mechanical state.

        -JS

        • >>Particles that can all have the same EXACT
          >>state, in quantum mechanical terms, are called.
          >>They fill and occupy available states in a
          >>certain way, described by a Bose distribution.
          >
          >Um, no. Bosons are (by definition) particles
          >with integer spin (0, +1, -1, etc.).

          The two definitions are more or less equivalent, according to a result known as the "spin-statistics theorem." Let me try to give a rough explanation of what this means (but not why it's true, because that's fairly complicated). Particles with integer spins (bosons) have Bose-Einstein statistics (note this is not quite the same as saying they form Bose-Einstein condensates). Bose-Einstein statistics mean, essentially, that when you exchange two of them, you get no effect. Fermi-Dirac statistics, on the other hand, have anticommuting particles so that exchanging two of them gives you a minus sign. Of course, this is implies that xx = -xx = 0, so you can never have two particles in exactly the same state when they obey Fermi-Diract statistics (that's the Pauli exclusion principle). The spin-statistics theorem assures us that particles obeying Fermi-Dirac statistics have half-integer spins, i.e., are fermions.

        • In response to your response :)

          1) As far as what a boson is, what you have stated and what I have stated mean the same thing. It just depends from angle you look at and whose definition you use.

          2) I never said photons could form a Bose-Einstein condensate. But, I do realize my thought was not quite complete.

          3) Believe me, even though I didn't show it, I know what lasers are and how they work.

          4) I do believe you have a point in your second criticism. However, wouldn't you agree that the phase of the photon is part of its quantum mechanical state? Every book I have read on the subject seems to think so.

          5) Also, I would like to refer you to this webpage:

          http://perso.club-internet.fr/molaire1/e_quantic 3. html

          Which seems to contradict the second part of your second criticism. Please let me know what you think.

          If you would like to discuss this further, please email me. I always like to make sure I have my understanding of quantum mechanics straight. I am a EE so I need all the help I can get.

    • Masers were the predecessors to lasers, producing microwave wavelength radiation instead of visible light. And saying that the research was done years ago is putting it mildly - IIRC masers were largely developed in the 50's, gas lasers in the 60's. They have absolutely nothing to do with this recent research.

      That said, it's possible that some reporter with absolutely no technical background abbreviated "matter laser" to "maser," but that would be a mistake since it causes immense confusion to anyone who remembers the original definition. If you meant "matter laser," then say so.

  • Okay... (Score:2, Funny)

    by sirgoran ( 221190 )
    So does this put us closer to getting transporters?

    I know more than a few folks I'd want to reduce to simple energy.

    Goran
    • Slashdot is 3 hours behind BBC. We need to do better slashdotters!
    • Even cooler (no pun intended) - does this get us any closer to phase-shift cloaking devices?
    • That's what high school science doesn't explain properly. Energy is a mathematical property...

      There's not really any such thing as 'pure energy'.

    • Re:Okay... (Score:2, Informative)

      by yzquxnet ( 133355 )
      I don't know how this stacks up as far as transporters go. But quantum entanglement has shown how transporters could be viable. It allows us to find both states of an atom. It is basically a run-around of the heisenburg uncertainty princple.

      As far as I know we have trasported a light photon. And, I think someone transported a bunch of 'something'? I can't remember, but it was a bunch of it.

      I guess the only thing preventing us from moving big stuff really comes down to the equipment and being able to handle the massive amount of data that would be generated in a 'timely' fashion.

      • Re:Okay... (Score:3, Informative)

        by mreece ( 38002 )
        >I guess the only thing preventing us from moving
        >big stuff really comes down to the equipment and
        >being able to handle the massive amount of data
        >that would be generated in a 'timely' fashion.

        Those are two major problems; there are plenty of others. There is a *huge* difference in "transporting" single photons and transporting larger objects. A photon has essentially two possible states (the helicity; left-handed or right-handed). Let's suppose all we needed was such spin information from every particle in a person's body in order to transport them. Try figuring out how many megabytes of information that is: we have 2^N possible values, where N is the number of particles. Divide by 2^23 to convert to megabytes. 23 is a lot smaller than N, so we may as well say it's still 2^N. N is really, really big. And now we consider that we need to get a lot more information right. Like the relative positions and velocities of the particles. We wouldn't want to transport someone and find his hand is flying away from him, would we? And how are we to extract this kind of information in the first place? Sure, entanglement is nice for say 5 particles, and for dealing with simple quantum states. It doesn't do you much good for much larger numbers of particles; and you generally have to have things beginning in the same place to entangle them.

        I'm no expert in this particular area, but I think I understand basic quantum mechanics well enough to tell you that transporters are, almost certainly, never going to happen.
        • Let's suppose all we needed was such spin information from every particle in a person's body in order to transport them. Try figuring out how many megabytes of information that is: we have 2^N possible values, where N is the number of particles. Divide by 2^23 to convert to megabytes. 23 is a lot smaller than N, so we may as well say it's still 2^N. N is really, really big.

          You seem to be saying that we need 2^N amount of space to store the spins? No we don't. You said it yourself: there are 2^N possible values that can be stored, and this requires precisely N amount of storage space. Say we have ten particles, that requires ten bits to store the spins, not 2^10 (1024) bits!.

          It's still a lot though -- how many particles are in the human body again? ;)

          • >You seem to be saying that we need 2^N amount of
            >space to store the spins? No we don't. You said
            >it yourself: there are 2^N possible values that
            >can be stored, and this requires precisely N
            >amount of storage space. Say we have ten
            >particles, that requires ten bits to store the
            >spins, not 2^10 (1024) bits!.

            Oops... I was in a hurry :-) Still, it's a large number of particles, so N is huge, and when you start addressing trying to also store their positions and velocities in any sort of detail (which is a bit of a problem in itself, due to Heisenberg) you see that even obtaining the data, much less storing them, is a bit of a problem. Not to mention that you still have to transfer that information to the site where the object is to be reconstructed, which takes finite time, sometimes large finite time.

            Thanks for pointing out that mistake.
            • I'll be the first to admit, I really don't know squat about quantum mechanics. I'm sure there are current problems keeping us from moving stuff bigger than single photons. But, I don't really see how storing positions and velocities in detail would still be a problem. You bring up Heisenberg, but Quantum Entanglement has all ready proven itself as a viable work around of the Heisenberg principle. Plus, as data technology advances, the storage and retrieval of the quantity of data that would need to be stored and retrieved may become a non-issue. It's hard to comprehend how quickly technology advances. Even when it is evolving right before your eyes.

  • As I recall (Score:3, Funny)

    by Water Paradox ( 231902 ) on Tuesday October 09, 2001 @01:39PM (#2407283) Homepage
    As I recall, I was able to create the Bose-Einstein condensate in my kitchen sink once. Man, all that hard work, and THESE guys get the Nobel for it... Well, better them than me, leaves me more time for programming...

  • Time to invest in Bose (Score:3, Funny)

    by nizo ( 81281 ) on Tuesday October 09, 2001 @01:42PM (#2407300) Homepage Journal
    Just imagine all the cool speakers they will be selling soon, with nobel prize winning scientists working for them!

  • New state of matter? (Score:4, Funny)

    by kypper ( 446750 ) on Tuesday October 09, 2001 @01:42PM (#2407302)
    ...thus discovering a new state of matter, the Bose-Einstein condensate.'


    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.

  • Congratulations! (Score:4, Informative)

    by rbruels ( 253523 ) on Tuesday October 09, 2001 @01:43PM (#2407309) Homepage

    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
    • Ass kisser!!! Sorry, couldn't resist.
    • Yes, a friend of mine happened to work in the lab this summer. Sadly I didn't learn very much about the research itself although I have been told that the recipients "suck at basketball".

    • Re:Congratulations! (Score:4, Funny)

      by Spy Hunter ( 317220 ) on Tuesday October 09, 2001 @02:16PM (#2407502) Journal
      Wow! I think every scientific experiment should have cool minigames [colorado.edu]!

      See the rest here [colorado.edu]!

    • It's interesting that this is the second Noble prize in 4 years (since 1997) received by NIST scientists working on low-temperature applications. Obviously these guys are well-connected.

    • Agreed. I was actually on a research team in the same building when they had their first confirmed breakthrough on creating BEC.

      They had a small presentation for anyone on campus that wanted to attend where they walked through the details of the experiment. Everyone from janitors to researchers showed up to watch. I remember they were asked if they were going to win the Nobel Prize for it, and they were quite modest.

      The original experiment only had a budget of roughly $50,000, which is nothing compared to the previous attempts that cost an order of magnitude more. I guess being clever with a magnetic trap is a good thing to keep in mind somedays.

      I also remember them saying that they weren't going to run to the press about it because they didn't believe in publishing to "JNYT". (The Journal Of The New York Times). I will always remember that display of scientific integrity.

      • I don't know if you are refering to the presentation that they gave back in Mackey Auditorium, but I must say that for a bunch of Physicists, they had one of the most entertaining technical presentations I have ever seen.

        I was a second year engineering student at CU at the time and was very impressed by the presentation that they gave, it was almost Penn and Teller like before they went into the technical information. At that point they lost me :)
  • The earlier /. article dealt with a variant that used the surface of a "chip" on which the condensate forms, making a "2-D" BEC. The earlier work that just earned the Nobel used lasers to supercool a gas of atoms.


    Unfortunately, I don't know enough about this stuff to know if the difference is profound, or just semantic...

  • Matter that oscillates in unison would have near zero resistance, thus would probably the best superconductor yet. This truly is a giant leap in superconductor research (regardless of it's actual intentions).
  • And I don't just mean what you can do with it. ;)
  • Any ideas what products may result from this eventually, or is it currently just a "neat thing involving lasers"?
    • this will be a powerful laser...

      superfine precision, able to make fusion possible

      perhaps drive-thru lasik surgery? =)

      --donabal

    • Re:But what does it *do*? (Score:4, Informative)

      by dragons_flight ( 515217 ) on Tuesday October 09, 2001 @02:19PM (#2407531) Homepage
      This Yahoo! News story [yahoo.com] about the Nobel prize includes discussion of potential applications.
    • This will be part of my project, the Alan Parsons Project to destroy the world with "laser' beams.


      You can see it on my website, www.SHHHH.com.org

    • There are a lot of ideas. My favorite is a more precise definition of the second (very low noise experiment, since the entire ensemble is in same state). Scientists need a better second. I'm not kidding.

      Now that I have given you a practical answer, here is a more interesting one. The technological advances that have come about in the search for the BEC are astounding. One example is laser cooling (Nobel Prize, 1997).

      From a physics standpoint, it answers a question that has been with us for more than 50 years (I don't remember when the condensate was postulated, but Einstein died in the 50s).

      For more fun, it blurs the distinction between atomic and molecular physics and condensed matter physics. That's always fun!
  • We should make a clone of Einstein. All most every physicist in the last 50 years has used his work as a basis. If we made a few dozen more of him, think of the technology we could have in another fifty years.
  • Check out the hardware [colorado.edu] that they apparently used for this. I assume its what they used to control the device.

    I guess its just a reminder that sometimes slow and simple out weighs fast and new. It'd be interesting to know just what sort of hardware and software they used to create this. The article on the Colorado page give some details, saying that diode lasers were used and that the apparatus was simple and inexpensive. It's neat to think not all cutting edge physics needs super expensive and complicated devices like cyclotrons.

    • That's one of the parts of this research that I heard about first. (Carl Wieman is my dad's cousin.) Not only were they able to get colder than anyone had been before, they were able to do it in a way that most research laboratories could replicate. Apparently cryogenic research has been "opened to the masses", so to speak. :)

      Bob Wieman

  • How to do it (Score:5, Funny)

    by hardburn ( 141468 ) <hardburn@nosPaM.wumpus-cave.net> on Tuesday October 09, 2001 @01:54PM (#2407390)

    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.)

    • Someone mod this guy up - that's some of the best bullshit I've heard since the last Presidential election season.

    • Yes, it gets really boring when you hit the Karma cap... the incentive to post quality reduces, and that to post crap increases.

      (QED)
    • Good post. You managed to mix enough truth in to make me look twice.

      They do get the atoms from a chemical decomposition, but not quite how you describe it.

      Let my explain the atom trap.

      The magnetic fields produce a spatial trap for the atoms (the most energetic leave, the least energetic settle in the region of lowest potential energy).

      The lasers trap the atoms in momentum space. Here is how it is done. The allowed transition energies for the atoms used are well known. The experimenter takes a laser that lases at the corresponding frequency (E=hv). She (her name is Sharon) then de-tunes it so that the atoms do not absorb any energy when they are at rest. However, any atoms that are moving toward the laser will see the beam as blue-shifted to the right frequency and absorb a photon. This photon has a momentum opposite to that of the atom, so it is slowed. It then emits the photon in a random direction. The net effect is that the atoms lose momentum. They use six lasers, two for each of the three orghogonal space coordinates.

  • Grammar nitpick: (Score:1, Insightful)

    by mblase ( 200735 )
    This year's Nobel Laureates have succeeded

    More like "had succeeded", really -- the condensate was achieved in 1995. Nobel prizes are usually bestowed several years after the achievement itself in order to give plenty of time for independent verification and to demonstrate relevance to the greater body of research and knowledge.
    • Their success hasn't stopped, so it is still more appropriate to use present perfect. Using the past perfect generally implies that the condition no longer exists, as in "Mark McGwire had been the home run record holder until Barry Bonds broke the record."

  • Most interesting property of BECs (Score:5, Interesting)

    by Macrobat ( 318224 ) on Tuesday October 09, 2001 @02:12PM (#2407480)
    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.

    • Re:Most interesting property of BECs (Score:5, Informative)

      by shawnseat ( 453587 ) on Tuesday October 09, 2001 @03:50PM (#2408037)
      Since cooling matter down to nearly absolute zero halts motion



      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).

  • ...they have caused atoms to "sing in unison" (Score:4, Funny)

    by sharkey ( 16670 ) on Tuesday October 09, 2001 @02:16PM (#2407501)
    A-one, and a-two...

    Cumbayah, My Lord, Cumbayah.
    Cumbayah, My Lord, Cumbayah.
    Oh, Lord, Cumbayah.

    Someone's splitting, My Lord, Cumbayah.
    Someone's splitting, My Lord, Cumbayah.
    Oh, Lord, Cumbayah.

    Someone's fusing, My Lord, Cumbayah.
    Someone's fusing, My Lord, Cumbayah.
    Oh, Lord, Cumbayah.

  • Does anyone know if a BEC maintains a mass consistent with the sum of its pieces, and how much comparative space it takes up?
    • Does anyone know if a BEC maintains a mass consistent with the sum of its pieces, and how much comparative space it takes up?


      Yes. Just like any other state of matter. Liquid helium below the lambda transition is a Bose-Einstein condensate also, but it is in liquid form rather than a gas form.

  • It sounds like one of the theorists (B)
    and it looks like other (E).
    It behaves very strangely compared to other matter.
  • I just heard on Swedish television that this could possibly be used in microchips in the future... at 20 nK I doubt it... Did the journalists find that out themselves, or has anyone else heard any more details?
  • Salon also has an article [salon.com] on the topic. It discusses the condensate in terms of a new "state of matter" (to go along with solid, liquid, gas, plasma?). It also mentions the most obvious applications are for precision measurement and nanotechnology.
  • Don't you find it a bit scary that during experiments like this, we're cooling matter to a temperature that's a billion times colder than the background ratiation of the universe (3K), creating, for a brief period of time, what is likely to be the coldest matter in the entire universe? Who knows what weird physics we could unintentionally unleash!
    • There's nothing like irrational fear to promote progress of mankind!
    • Its very unlikely that anything we create is the "coldest matter in the universe", I'm sure that there are ETs out there somewhere that can cool stuff better than we can. And I wouldn't bet against there being natural processes that put matter in a colder states. There are certainly processes which results in matter cooler than the microwave background.
  • here at MIT BEC [mit.edu], the webserver is a mid-power pentium that WAS runing win2k professional with IIS. but of course i get a call at 8:30 am (i'm a grad student i sleep late) with someone yelling "THE WEBSERVER ISN'T WORKING".


    that was because it was some dumbed down version of IIS that limited the connections to 10, and no one around here cares enough about windows to figure out the right registry settings (me neither).

    so instead of fixing it i downloaded apache and configged it in about 5 minutes. maybe less.

    since then it appears that web browsing has been a bit smoother. i checked the web log, which is normally about 200k on any given day, but by 4pm today is had grown to 17 MEGABYTES. ha! at it's peak we were serving around 10 megabytes per minute in pdfs, jpegs, etc. we have served 1.7 gigs so far today. whew.


    so now that it's fixed, come on in and check it out. go to ketterle, then research, and especially check out rubidium. :)

    and while i'm here, let me just say that wolfgang ketterle is one of the nicest people i have ever worked for. he, and everyone else here at MIT just kicks ass. wolfgang had gone to bed at 2:30am last night, and was awoken at 5:30am by some strange swedish dude...

    later,
    muerte

  • When the guys in Colorado first pulled this off a few years ago I happened to live in Denver.

    About a month after the fact, Stephen Hawking was in town, and gave a speach. Afterwards, various people got to ask Mr. Hawking questions - one of those was regarding the then-recent proof of this phenomenon.

    I don't recall the exact words, but with his usual brevity Hawking basically said that since this was known for 30+ years, it wasn't news. This was in front of an auditorium packed with some of the people responsible for the experiments. The hall was quiet for a moment there...

    Hawking's comments in no way detract from the difficulty and novelty of the experiments. It was just interesting to see the difference between the people who predict reality vs. those who prove the predictions.

    Jan

  • CNN & Science Illiteracy (Score:4, Insightful)

    by InfoVore ( 98438 ) on Tuesday October 09, 2001 @05:48PM (#2408576) Homepage
    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

  • Some Basic Info about Bose-Einstein Condensates (Score:4, Informative)

    by ChenLing ( 20932 ) <slashdot&ilovedancing,org> on Tuesday October 09, 2001 @06:09PM (#2408661) Homepage
    This is quite cool.
    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 :) as a particle slows down, its wave function widens.
    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. :) But it does get the point across.....

    Oh! I almost forgot. To cool the sample down to 20 nanoKelvin(?), this is what they do:
    1. They use Liquid whatever to cool it down by regular thermal processes.
    2. They trap the sample magnetically to confine it. This of course raises the temperature.
    3. Then they let the most active gas (the fastest moving therefore the hottest) out.
    4. Make the confined area smaller
    5. Repeat the previous two steps until very cool (down to the milliKelvin range I believe.
    6. Then they shoot *lasers* at it! I'm not kidding. The lasers (arranged at the right frequency and polarization) actually cools the suckers the rest of the way

    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....
  • This is the same reasearch that Hemos recently posted about.

    This is not surprising. Longtime readers of Slashdot know that Hemos routinely nails all of Nobel prize winners in a given year. The only drama was whether the Bose-Einstein guys would beat the particle accelerator guys [slashdot.org] and 'Young Einstein' himself Yahoo Serious [slashdot.org] for the physics prize.
  • Here's a question I've always wondered about regarding BECs. Say you make one out of a cloud of radioactive atoms. You hold the cloud together long enough to where if it were NOT a BEC, some of the atoms would decay. What happens? Does the waveform of the whole cloud change? When the cloud warms up, how does it decide which atoms not to reconstitute because they are "gone"?

    • Interesting question. The BEC is characterized by the total number of particles (atoms) within. Call it N. If the constituent atoms are radioactive, and one waits for decay products of a single radioactive decay to be detected in an external detector, then one will find an N-1 atom condensate, plus one set of decay products. Which atom decayed? Atoms (of the same isotope of the same element) in their ground (lowest-energy) states are indistinguishable entities, even in non-BEC systems (ever try to tell two electrons or two protons apart? same works for assemblages of same :-). It so happens that this indistinguishabilty has few experimental consequences at normal temperatures, but more profound consequences at very low temperatures. So one can't say which atom decayed- the question is ill defined.

      By the way, researchers at Rice University (Randall G. Hulet [rice.edu] et al.) made a condensate before Wolfgang Ketterle's group at MIT. MIT was third. Wolfgang is a great phycisist and gives a spectacular talk, but I bet the Rice people are feeling a bit left out about now, for good reason.

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