Atomic Optics Uses Light To Focus Atom Beams

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."

Comments

Both Memepool and Slashdot?

[bgraziano]

What are the odds that a story appears on both slashdot and memepool at the same time? Talk about a cross-over hit!

Re:Both Memepool and Slashdot?

[gfxnrrd]

Well, considering that it was posted to memepool 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 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.

....

[ConsumedByTV]

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?

[sharkey]

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.

--

The Doctor

[TechLawyer]

So the Doctor on Star Trek: Voyager might actually be possible, but he'd be really, really cold.

Laser Cooling

[Muerte23]

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

Re:1 uK isn't that low.

[mindstrm]

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?

[Sebastopol]

Can someone explain how you cool something with a laser? That seems a bit counter-intuitive.


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Re:cooling with a laser?

[Wind_Walker]

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 and search for "laser cooling".

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That's just the way it is

Re:cooling with a laser?

[styopa]

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) 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.

Bill Nye dead in bicarb explosion...

[Midnight Ryder]

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!

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

Re:Why is it so damn cold?

[Zachary Kessin]

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.

Hmmm, advances in holography?

[Mtgman]

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

OT: what is this a reference to?

[jovlinger]

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?

Re:OT: what is this a reference to?

[DrEldarion]

Started on the somethingawful.com forums... someone posted the quote from the game, and it kinda caught on, so, yeah, we ended up with a HUGE thread of people photoshopping pictures to include that caption.

After the hundreds of pics, and TShirts, it caught on to other forums, and one thing leads to another, everywhere is infected.

-- Dr. Eldarion --

Re:A very exciting time

[Mtgman]

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

Atomic Optics?

[pigpogm]

Sounds like nuclear powered drinks server, for measuring out *really* cold vodka.

Other ultracold atom links

[selectspec]

Ultracold plazma and good old Fermi degeneracy. Both from scientific american.

Re:Clarification

[sien]

No, no ! This is the Kalvin scheme. 200 Kalvin is one Hobbes. Hey, it makes as much sense as Fahrenhiet ;-)

Clarification

[Kozz]

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.

Re:Clarification

[Pogue Mahone]

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

Re:Clarification

[decipher_saint]

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 ;-)

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No the game never ends when your whole world depends

Kalvin

[Yoshi Have Big Tail]

Kalvin? 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.

NIST

[resonance]

They use the same technology in the latest atomic clocks at NIST. 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.

Re:1 uK isn't that low.

[fatphil]

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

Re:A very exciting time

[thex23]

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.

Re:1 uK isn't that low.

[esonik]

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.

University of Colorado, Boulder

[styopa]

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

The Joint Institute for Laboratory Astrophysics (JILA) 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 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.

Intel to Buy rights

[tonywestonuk]

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?

[popular]

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!

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Cooling atoms using laser light is not "new"

[Big Nothing]

This is exactly what Steven Chu, Claude Cohen-Tannoudji and William D. Phillips got their Nobel Price in Physics 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).

Thanks!

[mindstrm]

That, I understood. Appreciated.

HMm

[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 :)

1 uK isn't that low.

[fatphil]

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