Slashdot is powered by your submissions, so send in your scoop

 


Forgot your password?
Close
typodupeerror
×
Science

Atomic Optics Uses Light To Focus Atom Beams 81

Posted by michael from the star-trek dept.
dcshoes writes: "Nonlinear Atom Optics uses laser light to cool atoms to one millionth a degree Kalvin. At this low temperature, atom wavelengths are elongated, making the wave nature of atoms more easy to observe, and enable scientists to focus, reflect, defract, etc, atom beams. Atom lasers could lead to advances in, among other things, Nanolithography and Holography. Cool. Literally."
This discussion has been archived. No new comments can be posted.

Atomic Optics Uses Light To Focus Atom Beams More

Atomic Optics Uses Light To Focus Atom Beams

Comments Filter:
  • Theoretical advances from the study of the supercooled atoms aside, does anyone here have any idea how this technology might be directly put to some use?

    As I seem to understand it, we're currently limited to cooling a few dozen atoms at a time; sure, they get awful cold, but hypercooled atoms won't be a major component of any system until we can get the number up into the thousands or tens of thousands range.

  • What are the odds that a story appears on both slashdot and memepool [memepool.com] at the same time? Talk about a cross-over hit!
  • Atom Optics Technologies Could Be Phenomenal, UA Theorist Says

    Does this sound like a story title from "The Onion"(tm) to anyone else?


    Fight censors!

  • Crib Mountable? (Score:4)

    by sharkey ( 16670 ) on Friday February 16, 2001 @07:22AM (#426737)
    Does anyone make one of these to fit on a crib? The $CHILD_PROCESS is 6 months old now, and nothing pisses her off like going to bed. We need something to quiet her down. A quantum state of relaxation on her part would enable a good nights sleep for me and the SO.

    --
  • Atom holography is another stunning idea. Instead of making an image in light as done in conventional holography, atom optics would make the hologram of atoms. "What this means is, we could make a real, 3-dimensional replica of some object. We could copy objects." Meystre said.

    So when do we get food replicators, transporters, and holo-decks? All kidding aside, atom holography seems to make this all possible.

  • The Doctor (Score:4)

    by TechLawyer ( 182030 ) on Friday February 16, 2001 @07:29AM (#426739)
    So the Doctor on Star Trek: Voyager might actually be possible, but he'd be really, really cold.
  • So who will be the first to build a 'star trek' holodeck? Sounds like an atom laser would make this possible.

    I tell you, a while ago it was 'Quantum teleportation', now it's atom lasers. We are rapidly developing the sciences and physics of star trek! Transporters, and holodecks. What's next? I'm still waiting for some discovery in cosmology that will prove that warp drive is possible (in theory anyway).

  • weather reports (Score:1)

    by Anonymous Coward
    i think we should do wether reports
    in kelvin. good excuse to use big numbers:

    "its a balmy 304 degrees outside at our
    studios, with the forecast calling for
    temperatures falling to 299 degrees
    overnight.
  • except in equations you use "K" (Kelvin) and not "k" (wavenumber or something). and since it _is_ named for a guy named Kelvin, it should be proper to use it either way, like Gauss or Henry. /m

  • Laser Cooling (Score:5)

    by Muerte23 ( 178626 ) on Friday February 16, 2001 @07:30AM (#426744) Journal
    Laser cooling is an application of using the Doppler shift to selectively absorb photons propagating counter to the direction of the atom's movement. The laser is slighty red-detuned from some spectral line of the atom, so when the atom moves towards the laser, it absorbs a now correctly blue-shifted photon and gets a kick of momentum to slow it down. Since the atom emits the photon again in a random direction, then net result after millions of collisions is to slow its net velocity to zero.

    Since the atom is also emitting photons in random directions, it settles down to a minimum kinetic energy / temperature of about 240 microKelvin (for Sodium, for example). To cool atoms furter, you have to add in magnetic traps, then selectively "heat" the hottest atoms with RF energy to "boil" off the highest part of the temperature distribution to result in a lower average temperature of the condensate.

    Check the MIT Center for UltraCold Atoms for more details.

    Muerte

  • It's been posted on slash before, at that. I think I still have the aperture through which the first laser-cooled atoms passed...my basement is a mess. (FWIW, one of my professors assisted Phillips, and actually inherited the original apparatus).
  • All your base are belong to us!!
  • A friend of mine is doing some laser-cooling research at Innsbruck University, Austria. On their homepage [uibk.ac.at] they have links to workgroups including the Hänsch group and the Ketterle group mentioned in the article (first and last picture).
  • Thanks to these focused atomic beams, all your base are belong to MiG!
  • A couple of messages ago, two people mentioned the creation of holodecks and replicators. In theory this would work, but only at a temperature of one millionth of a kelvin... Once a person even touches the thing that is replicated, the cooled down atoms would heat up again from our body heat, thus "ruining" the replicated item. As for holodecks, that may be a different story seeing as how you can make holograms appear and disappear on command. You can slow down the atoms by cooling them as previously stated, then "arrange" them to create an object (in theory), to make the object "disappear" you only have to raise the temperature surrounding the cooled down atoms. The only problem with this is that you couldn't get close enough to it seeing as how the temperature around the atoms is so cold... If you just want to look at an object from behind a glass wall that keeps the room that you're in warm, and the room the objects in cold, I could see that happening... but otherwise, don't give your hopes up.

  • Re:1 uK isn't that low. (Score:3)

    by mindstrm ( 20013 ) on Friday February 16, 2001 @06:38AM (#426750)
    Can you explain what a 'negative' temperature would be, given that 0k is the absence of all temperature? I assume this is some kind of quantum theory thing...

    can you elaborate a bit? I've never heard of 'negative heat' before.

  • cooling with a laser? (Score:3)

    by Sebastopol ( 189276 ) on Friday February 16, 2001 @06:40AM (#426751) Homepage
    Can someone explain how you cool something with a laser? That seems a bit counter-intuitive.


    ---
  • Sorry - should have held back a minute or two before posting the last thing - here's the figures:

    http://liisteri.hut.fi/Archive/Spin_temperature. jp g

    FatPhil
    -- Real Men Don't Use Porn. -- Morality In Media Billboards

  • Damn... I can't help it. Seeing Bill Nye the Science Guy mentioned on here means I have to post this:

    Bill Nye killed in Experement! [theonion.com]

    Yes - it's a joke (it's at The Onion, of course it's a joke!)

  • Damn near imposible to do stuff like this at anything but super cold temps, there is just to much thermal energy in room temperature air (or anything else) which knocks stuff out of whack.
  • With an operational temperature of less than one Kelvin, I don't think this will catch on for mainstream holographic applications. It's hard enough to find a hot babe in real life, now you're going to tell me that the virtual ones are all literally frigid?

    Damn.

    Steven

  • Re:How about Zero? (Score:1)

    by Anonymous Coward
    I think someone theorized that that is when matter ceases to exist. maybe negative(opposite) light?
  • >

    Only in the US. In the UK it would more properly be 'one millionth of _a_ Kelvin'

    -Ciaran
  • Atom holography is another stunning idea. Instead of making an image in light, as done in conventional holography, atom optics would make the hologram of atoms.
    "What this means is, we could make a real, 3-dimensional replica of some object. We could copy objects." Meystre said.

    So we can use these atom beams to shove individual atoms into place and replicate things.

    I can understand this from a nano-manufacturing standpoint(few atoms to move into place would make this type of manufacturing more viable than having to assemble billions or trillions), but what about large-scale replication?

    Since the particles have to be cooled to such a low temp before they can be maniplated with these atom beams, what happens when the replicated object warms up?

    Now I need to go off on a huge long rant about the stupid lameness filter. The above post was rejected almost a dozen times with


    Lameness filter encountered. Post aborted.

    Reason: Junk character post.


    Now, I sent email to CowboyNeal about this because this is obviously not junk characters. I don't even have very many special characters. I've tried all kinds of mutations on this post. In the end I've deleted all the content I pasted from the article and re-typed everything. This is wrong guys, just plain wrong. Fix the freaking filter.

    Steven
  • I'm tired of getting atoms to "one millionth of a degree from zero." Let's just stop it entirely already!

    And I'm getting tired of our best accelerators which can only accelerate electrons and other subatomic particles to 0.999999c. How about getting to absolute c?
    __ __ ____ _ ______
    \ V .V / _` (_-&#60_-&#60
    .\_/\_/\__,_/__/__/

  • 0K != No energy,

    there is such a thing as zero-point energy.

    I'm not going in to it now but basically it's all Heisenbergs fault.

  • Well, there is no such thing as "absence of temperature (what you mean is probably "absence of energy" and there is no such thing either but for different reasons) but let's go for "negative temperature" (and let's not confuse temperature with "heat", "heat" is a form of Energy):
    You can define Temperature by means of statistics: Let's say for a System of 100 spins in a magnetic field, so each can have high or low energy. Now you define temperature by looking at the statistics, by simply counting how many spins are in "high" state. Since "lowering the temperature" means "giving away energy" the lowest Temperature for the System is all spins in "low" state. At higher temperatures the spins are more evenly distributed over the possible states, the most "even" distribution being 50 spins "high", 50 "low". In that case the systems temperature is so high, that the energy difference ("high"-"low") doesn't matter anymore, but since a hotter system will always tend to cool down by giving energy to cooler systems (with a lower temperature) this system is likely to give away energy to (almost) any other system and cool down a bit, so the statistical most likely "even distribution" is compensated a little by the fact, that the System tends to lower it's temperature by giving away energy (so there are more spins in "low" state than in "high" state). Since an evenly distributed system would give away energy to any other system, regardless of that systems temperature (if it's not negative), we can think of such a system as having infinite temperature (since it must have a higher energy than all the other systems it gives energy to).
    Now there is a situation you can not reach by simple heating (heating meaning here introducing more randomness), it's an "inversed" situation, where more spins are in "high" state than in "low" (now the more energy you put into the system the more ordered it becomes). In that case the Formulas give you "negative temperatures" (you can reach them by artificially pushing the spins to "high" state). This is confusing, since the system has higher energy than one with positive temperature, hence negative Temperatures are "above" negative temperatures, it makes much more sense if you look at 1/T since this goes from positive to negative continuously.
    Normally you can create such systems only with a limited number of spins, (i think it might occur in pumped lasers too) but not in macroscopic systems. Now the problem with this example is, that thermodynamics is all about having a lot of statistics (it makes not much sense to talk about the temperature of a single spin), so fluctuations can be neglected. Hence a system with only 100 spins is already a little borderline, but by adding a few zeroes here and there that can be helped. For an experimentalist it's a little harder to add those zeroes though :-).

  • All your base are belong to us!!


    Erm. I've been seeing this alot, lately. Memepool had it, as did the acme heartmaker linked off that page (cute!).

    Can anyone explain why this phrase in broken english is gaining popularity? Are the elite doods getting as sick and tired of their numerals as the rest of us? Is it a reference to something beyond my ken, or just something someone made up?
  • That's restricted geek information.
  • Zero Wing, a very poorly translated game.

    Here is an amusing "music video" featuring some of the screen captures from the game.

    http://www.imsa.edu/~dank/AYB2.swf
  • Hmm, I'm wondering if it's worth it to read replies anymore. Here's a thought, on the user info page, let us know who, as in username, replied to our posts. That way I don't waste my time reading replies from idiot ACs. Just a thought.

    Steven
  • It comes from the really bad translations in the game Zero Wing for genesis. What the flash animation here [rmitz.org] has to do with anything is beyond me. I don't care about karma. Save your mod points for someone who does.
  • Sounds like nuclear powered drinks server, for measuring out *really* cold vodka.

  • Other ultracold atom links (Score:4)

    by selectspec ( 74651 ) on Friday February 16, 2001 @06:14AM (#426768)
    Ultracold plazma [sciam.com] and good old Fermi degeneracy [sciam.com]. Both from scientific american.

  • Re:Clarification (Score:4)

    by sien ( 35268 ) on Friday February 16, 2001 @06:14AM (#426769) Homepage
    No, no ! This is the Kalvin scheme. 200 Kalvin is one Hobbes. Hey, it makes as much sense as Fahrenhiet ;-)

  • Clarification (Score:4)

    by Kozz ( 7764 ) on Friday February 16, 2001 @06:11AM (#426770)
    The temperature scale is "Kelvin", not "Kalvin". And the measurements are known as "Kelvins", not "degrees Kelvin" (any physics student knows this). The proper phrase would be "to one millionth of one Kelvin".

    Thank you.


    Quidquid latine dictum sit, altum viditur.
  • Kalvin [ucomics.com]? Isn't a bit unfair on Hobbes to reduce Kalvin so much? Would you like such small friend?

    Seriously though, it's Kelvin, named after the scientist, and it's not degrees Kelvin, it's simply Kelvin, since Kelvin is an absolute scale.

    For those who don't know, 1/1000000th of a Kelvin is very very slightly above absolute zero, the temperature at which there is absolutely no molecular movememnt (because there's no heat energy). 0 K = absolute zero - 272 degrees Celsius.

    Kelvin is the same as the Celsius (1 K= 1degree C), but with absolute zero as 0 instead of 0 as the freezing pt of water at normal conditions.
  • Unless he happens to be referring to a small one of these. [mactyre.net]

  • I suppose, with it being such a small fraction of a Kelvin, we could call it Kelvin Klein.
    --

  • NIST (Score:4)

    by resonance ( 106398 ) on Friday February 16, 2001 @06:13AM (#426774) Homepage
    They use the same technology in the latest atomic clocks at NIST [nist.gov]. Pretty cool stuff, they have a video there to check out that shows how the lasers make a ball of supercooled cesium and fling it up in the air to make a clock. Check it out.
  • Or, indeed, one microkelvin. 1 uK (given the absence of a mu on my keyboard).

    This is what we have units for, after all.
  • Behold! The only working phaser ever built!

    cryptochrome

  • Re:1 uK isn't that low. (Score:4)

    by fatphil ( 181876 ) on Friday February 16, 2001 @06:50AM (#426777) Homepage
    I always direct people to the Usenet Physics FAQ:

    http://math.ucr.edu/home/baez/physics/neg_temper at ure.html

    They say it better than I could, and what's more they understand it, I just parrot it.

    FatPhil
    -- Real Men Don't Use Porn. -- Morality In Media Billboards
  • I gave up on correcting the editors here a long time ago.

  • Re:cooling with a laser? (Score:5)

    by Wind_Walker ( 83965 ) on Friday February 16, 2001 @06:54AM (#426779) Homepage Journal
    Basically, this is how you cool with lasers: Imagine you have six lasers, all pointed at the same place, and all in perpendicular directions (imagine a cube with a laser pointing directly at the center of each face, but the cube is actually transparent, the laser beams oriented towards each other)

    Now we put some amount of mass right at the point where the 6 laser beams cross. The mass at the center will be hit by some photons from one of the lasers (for argument's sake). This will cause the mass to absorb the momentum of the photon, as well as excite the particle. The excited particle will then emit another photon in a random direction. However, there will be some recoil from this photon being ejected. Instead of being pushed away by this ejection, the particle is "persuaded" by the other lasers to stick around, so to speak. The process then repeats, but it takes about 10 minutes. Since the particle has lost momentum (to the ejected photon) it has less energy (in the Physics department here, we call it "tired").

    Eventually, the mass at the center gets so "tired" that it falls into a quantum state of relaxation, as described by Schroedinger's equation and its wavefunction. Interesting things happen when it gets incredibly cold, and that's what the article is talking about. This was a very simplistic explanation, so if you want something more, just head over to Google [google.com] and search for "laser cooling".

    ------
    That's just the way it is

  • Moderator go home...
    The second link is a
    http://www.bignamesite.com&temptinghook@my.ip.ad dr ess/

    i.e.
    http://user&password@my.ip.address/

    You're logging into the (AC) guy's site with username "www.cnn.com"

    Whoever moderated that up should retire.

    FatPhil

    -- Real Men Don't Use Porn. -- Morality In Media Billboards
  • It was only ever fired once, and that was to keep William Shatner from recording another album.

    --The Comic Book Guy
  • Hahhah!
    Nope, it's probably not a bad site, it's just "false advertising".

    The "goat" will live forever, won't it?

    FatPhil

    -- Real Men Don't Use Porn. -- Morality In Media Billboards
  • try this out: www.mcutter.com and click on the physics paper
  • I don't care if they spelled it backwards, the STORY is what we're supposed to be interested in. For the most part I try to ignore the witless banter that accompanies most stories posted on /. as they are usually thrown in as an afterthought (at least thats what I think). Critiquing their grammatical (or in some cases, logical) content is a waste of time.

    Ah well...

    Maybe Kelvin is the 'recommended retail spelling' and in this case the vendor decided to mark it down to Kalvin, a dumber, cheaper alternative spelling ;-)

    -----
    No the game never ends when your whole world depends

  • As many people have already said... It's Kelvin. And no, he doesn't hang out with Hobbs.

  • I agree, Steven. I too have encountered the pissy behaviour of the lameness filter, just because I wrote a poem reply to a Troll that used repetition. I think if you are using a named account, you should be cut a lot more slack.

    And as for the atomic holography... I'd be surprised to see applications like this for ordinary objects. Scanning objects to determine their structure might be possible, but you would probably prefer to go vector here, not bitmap. Maybe you could use this to grow crystals of carbon, silicon, and iron, other basic materials. You could even dope them.

    I think matter computers are going to be wild. Just the fact that it's the exact opposite direction we are going now (ie: using energy to direct matter instead of using matter to direct energy) tells me this is a paradigm-shift kind of tech. Maybe with quantum computers made from atomic lasers, we can come up with a whole new way to model things (put some handles on chaos?), and THOSE will allow us to know how to build complex--even living--structures, one atom at a time.

    It's something science fiction has promised us: so why shouldn't it be so?

    Now, if only we could use lasers to transcend time and space, become enlightened, and quit abusing ourselves and our environment. That would be nice.

    We thieves, we liars, we vandals, and poets. Networked agents of Cthulhu Borealis.

  • "Atom holography is another stunning idea. Instead of making an image in light as done in conventional holography, atom optics would make the hologram of atoms. "

    "Atom holography would create actual replicas, rather than images of light."

    "What this means is, we could make a real, 3-dimensional replica of some object. We could copy objects." Meystre said.

    "All of the individual steps to do this with nonlinear atom optics have been demonstrated. It's just a matter of making it work all together. I think it will happen in the next two or three years."


    Whoa! Sounds like a transporter!

  • Some thermal-non-equilibrium configurations can be described by a negative temperature (e.g. the population inversion in the active medium of a laser).

    First a clarification of the term "temperature":
    Temperature is a number that describes the distribution of a set of particles over the energy, i.e. how many particles have what energy.

    At T = 0 Kelvin all particles would have 0 energy (not possible). At T > 0 K there are some particles with higher energy: the higher the energy, the fewer particles you will find that have this energy. The exact distribution is given by a formula called "Maxwell-Boltzmann-Law" (or its quantum mechanical analogues) which gives the number of particles at an energy E for a system having the temperature T.

    Now at T < 0 K the distribution is: the higher the energy, the MORE particles you will find that have this energy. The reason why this is called a negative temperature is that sometimes such distributions can be described by the Maxwell-Boltzmann formula with a negative T.
    This kind distribution is not stable, it's called "non-equilibrium", because most particles with high energy will tend to give energy to particles with lower energy and the system will approach a T > 0 K distribution.

    "Heat" is something different than temperature, it's basically a synonym for energy.

  • If that being the case, when are the stickers coming out with Calvin peeing on a physics book? I want one for the back window of my car...
  • I thougth absolute zero was -273.15 degrees Celsius (to 2 dp) ?
  • Oh come on. As if you couldn't have thought of that final pun? Assume that enough different people are posting the same article so that it really doesn't matter which is chosen, or how it works. As long as they're not using d00dsp34k I honestly don't care what it says, because I go read the article myself. I just want to know it exists, and if it's something I'm interested in.

    - W
  • I believe that CU Boulder has the record for ultra low temperatures.

    The Joint Institute for Laboratory Astrophysics (JILA) [colorado.edu] at CU Boulder has been producing true Bose-Einstein condensates (BEC) since 1997 and Fermi-Dirac digenerate gasses since 1999. I say true BEC because technically superfluid helium-4 and helium-3 exhibit some of the properties of BECs, although they can be called BECs they are do not follow all of the statical mechanics that a true BEC follows.This press release [colorado.edu] about the creation of the first true BEC mentions that they were able to get rubidium atoms to 20 billionths of a degree K, or 20 nK in 1995. They have reached much lower temperatures since then, I think a year and a half ago they had something like 900 pK. From what I was told less then 6 months ago the now much large group of atomic physicists working on BECs in the JILA tower still hold the record.

    To learn more about the BEC follow this link [slashdot.org].

  • actually 273 and 1/1000000 K is below the freezing temperature of water under the conditions you described.
  • The explination about laser cooling by Wind Walker is a very good one but one can only reach something like microkelvin with laser cooling. In order to cool something to an even lower state one needs to create a magnetic trap.

    A magnetic trap basically consists of creating a potential energy well using magnetic fields with a "lip" at a certain energy, think of a vase. Anything with energy higher then the "lip" will be able to leave the magnetic trap, taking its energy with it. When particles collide the energy is transfered, which can have one of two effects: 1) make the energy of the two particles more equal; or 2) Increase the energy of the one with more energy and decrese the energy of the other particle. If, after the collision, the 2nd things happens AND the energy of the first particle is now higher then the "lip" it will leave the trap decreasing the total energy of the system, ie lowering the temperature. Once the system hits an equalibrium and no more, or very few, particles are leaving the system one lowers the energy of the "lip". This allows more particles to be ejected from the system, again lowering the energy and therefore the temperature of the system. Wash, rinse, repeat. After this process has been done quite a bit one releases the trap and lets what is left of the particles that have been trapped to expand rapidly. Which, if you have studied thermodynamics then you know, lowers the temperature even lower. The trick is keeping enough particles to have enough data. This technique has yet to hit a limit on how low it can go.

    Right now the University of Colorado, Boulder, Joint Institute for Laboratory Astrophysics (JILA) [slashdot.org] has been able to reach temperatures lower then 900 pK (or 0.0000000009 K). From what I have been told, the coldest place in the Universe that we know about is in the JILA tower where they create the Bose-Einstein condensates [slashdot.org].
  • Further clarification: 1. KELVIN does not have a plural, just Kelvin or K. 2. 0(Zero)K = -273.16 degrees Celcius (C)(1742), -459 degrees Fahrenheit (F) (1709), -219.2 degrees Reaumur (R) (1730) and -411 degrees De Lisle (D); I forget the date. For example, Nitrogen is liquid at 77K.
  • Hmm, does this remind anyone of anything else. Recall the technique using cold to slow the speed of light down to speeds slower than my car. We should see some advances in optical switching and networks out of this. Interesting science

  • Intel to Buy rights (Score:4)

    by tonywestonuk ( 261622 ) on Friday February 16, 2001 @06:20AM (#426798)
    Latest News: Intel to buy rights to laser - Technology required to keep next future Pentium V processor from overheating...... :-)

  • Why is it so damn cold? (Score:4)

    by popular ( 301484 ) on Friday February 16, 2001 @06:20AM (#426799) Homepage
    When will scientists figure out how to do cool stuff like this at room temperature? Bill Nye amd Beakman and Jax can perform all kinds of science wizardry with an empty bottle of Coke and a tablespoon of baking soda!

    --

  • What could an atom beam be used for? Maybe a really really fine tipped pen?

  • Cool CNN coverage (Score:1)

    by Anonymous Coward
    CNN [cnn.com] has news coverage of the technology, including some great pictures [209.242.124.241] of light focusing principles.
  • Can anyone else see the amazing potentials of an atomic mirror? Cloning might have the potential to become a trivial issue of the past as objects (organic and non-organic) can simply be "replicated". One does have to realize, before getting carried away, that at present this can only be accomplished at extremely low temperatures...but still...

    Imagine what the MPAA will say as we use our atomic mirrors to dupicate their precious DVD's, atom by atom.

  • Re:Both Memepool and Slashdot? (Score:4)

    by gfxnrrd ( 217377 ) on Friday February 16, 2001 @07:10AM (#426804) Homepage
    Well, considering that it was posted to memepool [memepool.com] YESTERDAY and the "poster" on Slashot even ripped off the final pun of that article, I'd say the odds had nothing to do with it. I notice a lot of memepool [memepool.com] articles are reposted here, often verbatim. The Slashdot editors should be more careful about reviwing submissions to make sure they aren't just ripping off content from other websites. It just makes Slashdot look bad.

  • Sounds like a pretty expensive battery ;-)

    -Helmet

  • This is exactly what Steven Chu, Claude Cohen-Tannoudji and William D. Phillips got their Nobel Price in Physics [slashdot.org] for back in 1997. They've been working with this kind of stuff since approx. 1985. Cool stuff, though (no pun intended).

    Sorry if this info has been posted earlier on the list, I didn't have time to read through it, just wanted to inform you geeks (and geekettes).
  • Comment removed based on user account deletion
  • A few people have suggested Star Trek style replicators, and have been rebutted the effect that the objects could only exist at 0K. Why?
    Why can an object not be created at 0K and then allowed to heat up? I can see that that process would destroy biological matter, and would possibly cause problems with any sort of molecular bonding, but surely once you arrange the atoms of e.g. a metal some way, it will stay like that.

    Maybe once the kinks are worked out:

    To heat your meal:
    From chilled: 3mins
    From frozen: 12mins
    From suspended animation: 7hrs

    -- Jamie Webb

  • Helsinki University have acheived macroscopic temperatures measured in pK (pico-Kelvin). I believe that the most recent record was circa 18 months ago.

    I feel obliged to plug this result as I had dinner with the daughter of one of the professors only 2 weeks ago.

    I had heard she was rather frigid. True? Sorry, had to be said. Mod me down if you must. It was worth it!!!
  • That, I understood. Appreciated.

  • HMm (Score:2)

    by Anonymous Coward
    A Danish scientist, Lene Hau, is using the same technology in her Harvard lab, she cools down Caesium (I think this is it) and sends light through it. The light is then stored as information in the Caesium atoms and thus is brought to a complete stop. She can hold the light there for as long as she wants, and release it again when she wants...pretty cool stuff :)

  • K = C + 273.15

    So absolute zero is at 0 K or -273.15 C.

    Just 1.15 degrees off.

  • I'm tired of getting atoms to "one millionth of a degree from zero." Let's just stop it entirely already!

  • 1 uK isn't that low. (Score:4)

    by fatphil ( 181876 ) on Friday February 16, 2001 @06:28AM (#426814) Homepage
    Helsinki University have acheived macroscopic temperatures measured in pK (pico-Kelvin). I believe that the most recent record was circa 18 months ago.

    I feel obliged to plug this result as I had dinner with the daughter of one of the professors only 2 weeks ago.

    There are pathological non-macroscopic situations where lower _even negative_ "temperatures" are involved. However, there require setting up bizarrely improbable situations with only small numbers of atoms (hence this is not a macroscopic situation). The laws relatiing entropy to temperature prove that in order to be that improbable, the temperature must be negative!
    (Method - line up polar atoms in a strong field, reverse the field as quickly as you can - voila you now have almost every atom pointing in the wrong direction - now _that_'s improbable.)

    Phil
    -- Real Men Don't Use Porn. -- Morality In Media Billboards

Slashdot Top Deals

A morsel of genuine history is a thing so rare as to be always valuable. -- Thomas Jefferson

Close