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Cooling With Lasers
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"Look! There! Evil!.. pure and simple, total evil from the Eighth Dimension!" -- Buckaroo Banzai
"Look! There! Evil!.. pure and simple, total evil from the Eighth Dimension!" -- Buckaroo Banzai
First Ontopic posting.. (Score:1)
We have trapped lithium and cesium atoms in the focus of a CO2 laser beam at a wavelength of 10.6 m. The atoms are confined by the optical dipole force arising from the interaction of the induced atomic dipole with the far off-resonant light field [1 [slashdot.org], 2 [slashdot.org]]. Due to the large detuning of the CO2 laser light from any atomic resonances, photon scattering can be completely neglected. Different atomic species or even molecules can in principle be confined simultaneously in the same trapping volume. The trapping force is independent of the internal atomic state in contrast to, e.g. magnetic traps, where only specific sub-states are confined.
Due to the very low photon scattering rate, the far detuned CO2 laser trap offers unique possibilities. It allows for long storage times of atoms and molecules in any sub-state or combination of substates, e.g. the study of atomic spin relaxation, photoassociation of ultracold molecules and investigation of collisions in two-species mixtures. Starting from our combined magneto-optical trap for Li and Cs atoms [slashdot.org], we plan to transfer cold lithium and cesium simultaneously into the CO2 laser trap with the prospect to sympathetically cool lithium with the optically cooled cesium [3 [slashdot.org]]. Lithium and cesium represent a particular promising combination for sympathetic cooling. At temperatures obtained with laser-cooled cesium, bosonic (7Li) and fermionic (6Li) lithium would reach the quantum degenerate regime at moderate densities already.
On Laser cooling (Score:2)
In a storage ring, only the longitudinal degree of freedom can be directly cooled very efficiently. However, we could demonstrate tranverse beam cooling by a coupling through Intra beam Coulomb scattering [4 [slashdot.org]]. In addition, we have introduced a novel method for indirect transverse cooling based on a single-particle interaction of ions with the laser light (dispersive cooling [slashdot.org]).
In the course of the last year, we have made important progress in laser cooling towards crystalline beams which has led us to new interesting results. The observations are consistent with the formation of a crystalline ion beam:
Re:What is the point of this (Score:1)
Re:GUIDE TO MODERATION (Score:1)
Underrated=Moderator did like it for no good reason
The point is obvious! (Score:3)
You mean you don't already know?!?
Think people!!!
Here we can kill two very important computer problems with one proverbial stone! And even reap a nifty side effect as well!
- Problem one: The heat problem. Computers have it, and this represents an alternative to other methods. It has a few definate advantages over traditional heat sinks.
- Problem two: Just think how cool the inside of your computer could look with some of these babies installed! Flashing lights! Cool lasers! You might even be able to get them to do cool scanline effects! You might even end up leaving your case off, to both facilitate air flow, and to enjoy the cool techo-ness of the inside of your computer! Get a fog machine, and your heat sink could probably match anything you see at a concert or other "professional" laser show!
- Nifty side effect: Lasers are cool! They are one of those items which for some reason, are simply undeniably cool. (Other examples include lightsabers, NINJAs, and walls covered entirely by TV screens and flashing LEDs.) So if you put something that cool in your computer, then your computer will become slightly cooler by proximity, and you, as the owner of the now coolness-enhanced machine will find yourself reaping the benifits of coolness as well!
And THAT's what the point is!A point of ideology? (Score:1)
(never mind the fact that it almost always ends up being useful in the end anyway... Look at the branch of mathematics known as number theory: For many years, college professors who taught it would brag that it was one of the few fields of study that was completely and utterly without practical application. Now it's one of the central fields of research in cryptology. That'll teach'em to brag.)
Could these lasers be used to... (Score:1)
Re:What is the point of this (Score:2)
That is pure basic research. It may be that for several years there isn't any "practical" gain from this research, but the same goes for quite a lot of current scientific research. It is the foundation upon practical appliances can be built.
E.g. think of electricity. It is known for several hundred years, but till the end of the 19th century nobody thought that it might have any use at all. Along came the telegraph and the first light bulb, and this viewpoint changed quite drastically.
At very low temperatures, previously unknown properties of matter can surface which nobody even thought they existed, e.g. superconductivity. It was discovered more or less by accident, and this discovery wouldn't have been possible without the low temperatures of liquid Helium.
If we were to abolish basic research, because we don't have any immediate gain from it, our technological advance would come to a slow, grinding halt. BTW when the first laser was constructed, nobody thought about its possible application in medicine. And not all lasers are equally good for everything. You wouldn't try an operation with a cd drive laser or one of the high energy systems standing in the physics building where I work! :-) Those babys are so fscking powerful, the air molecules crossing their beams fluorescate.
Re:What is the point of this (Score:2)
Cooling to really low temperatures is important for physicists to study the properties of weird things like Bose-Einstein condensates -- macroscopic amounts of stuff behaving in a quantum manner. This, as usual, helps with our understanding of quantum mechanics in specific and physics in general.
However, you may not be satisfied with such a response -- not practical enough? Cold atoms are essential for decent atomic clocks, because such a clock works by measuring the natural frequency of oscillation of the atoms. If they have heat too, they wobble due to this temperature as well as due to the natural frequency so you get a lower signal-to-noise ratio.
Atomic clocks are also very useful for physics -- some aspects of special relativity have been confirmed directly by this (twin paradox, anyone? [syr.edu]).
Ultimately you might ask what the practical point is for this too. Those funky global positioning satellites need accuracy of this order to work out where the satellite is at any one time and hence where you are.
Re:What is the point of this (Score:1)
Now, you have CD players, DVD players, laser surgery...
No, I can't think of any real, practical uses for this sort of thing - but you can bet that someone will.
Oh, and before you get all riled up about the amount of money being spent on this, let me assure you, it's peanuts compared to what is already being spent on medical research. Diverting the funds really wouldn't make a great deal of difference. I don't have any figures to back that up, but here in the UK, the NHS's bill due to litigation brought about by patients is about 2 billion pounds (IIRC); people not suing would free up an awful lot more money than people not doing research that you can't think of a use for.
Cheers,
Tim
This isn't new. (Score:1)
Jay
-- polish ccs mirror [prawda.pl]
uses of laser cooling. (Score:4)
It's the last of these items that is likely to prove the making of laser cooling. I don't know if it's happened yet, but there was talk of making the fundamental frequency standards (currently caesium atomic clocks) from laser cooled atoms.
thats a little technical (Score:1)
Cooling ATOMS not processors (Score:1)
Quite apart from the issue of how much heat can be removed by this method -- not very much -- there is the fact that for this to work you need to shine (at least) two lasers at your target from opposite sides.
Basically, this is an old story submitted by a clueless reader, and posted by a clueless editor. Like most of the rest of what is on
trolling for education (Score:1)
I'm going to be the first to mention, for no apparent reason, that "laser" is actually an acronym, standing for
Light
Amplification by
Stimulated
Emission of
Radiation
At least this troll was educational.
Where's the news??? (Score:1)
And for all those asking "What is it good for?": There are lots'n'lots of experiments which need atoms cooled down to nearly 0 Kelvin. And these experiments are needed to better understand quantum mechanics. And we need a better understanding of quantum mechanics to be able to build even smaller and faster CPUs in the future, as quantum mechanical effects (like tunneling of electrons through isolators) are already showing up in today's microprocessors. And I'm sure someone with more knowledge than me in this area could give you dozens of other examples where laser cooling has practical impacts.
But, as I said, this story is not news and hence deserves to be trolled to death.
Re:A point of ideology? (Score:1)
(*irony*)Hooray for tenure !!!!! Hooray for academic freedom - and the right to challenge received wisdom !!!!(*/irony*)
Research is important. Research for no reason, for the 'pursuit of knowledge for its own sake' is less justifiable, particularly when public money is being spent on it. 'Pickled sheep' come to mind. Problem is, in a society where a smaller and shrinking percentage are actually inputting tax-bucks into the system, accountability will become more of an issue to academics in future. Tub-thumping and rhetoric will not make this go away - the golden rule is that "The man with the gold makes the rules".
Re:The point is obvious! (Score:1)
Lightsabres are clearly the coolest things ever. As you mentioned, lasers are cool. Swords are cool. Laser swords are exponentially cool. A guy I know believes that any situation can be made cooler by adding a lightsaber.
Re:The point is obvious! (Score:1)
Once someone writes the WinAmp plugin, you won't have to go to the planetarium for the Pink Floyd laser light show!
--
News... (Score:1)
Stop linking cooling with overclocking! (Score:3)
Just when I thought that we already have more than enough overclocking news stories (on /. and everywhere else), here comes another one. What makes it worse is that it is not even a true overclocking news story at all: first, it has nothing to do with overclocking, second, this is not news, third, there is barely a story in this one -- at least not in the way it is presented.
Let's tackle the easy one first: the "news" part. As many have already pointed out, this is hardly news for anyone who knows his way around the field of modern physics. Even if you do not major in physics or read journals each month, you are supposed to remember that three researchers, Steve Chu, Claude Cohen-Tannoudji, and William D. Phillips received the 1997 Nobel Prize in Physics [nobel.se] specifically for the development in laser cooling. I could understand that the editors at HOCP might not have the time or expertise to realize this fact (besides, they never really mentioned overclocking), and I could understand that some readers of /. might be unaware of such fact. But I really expect a lot more from our /. editors. If we need to post science stories, get somebody who knows the business instead of letting stuff posted just because some layman think it's "cool". It is unlikely that we cannot afford it, right?
Second, laser cooling has absolutely nothing to do with overclocking. This is pretty easy to understand after you see what the technology is all about. (I am not a physics major, but have read quite a lot about it a while ago when conducting some research. Still, please correct me if I am wrong.) There are a lot of ways to cooling, and most of them are based on the idea of using something colder to absorb the heat from the object we intend to cool. This works nice under normal conditions, but fails miserably when you need to cool something from 0.1K to 0.000001K -- because there is nothing cooler out there.
Microscopically, heat is represented by the vibration of molecules. The greater the vibration, the hotter it is. So if we could somehow reduce the vibration of molecules, we can effectively cool it. That is where laser comes in. When you have got hold of the vibration pattern of a molecule (or a small group of them), all you need to do is to fire a small burst of laser and use the momentum of the photons to cancel the momemtum of the atoms. So the atoms will slow down, and its temperature will reduce.
Obviously you do not want to (and cannot) do this with your processor, because it is too large, and freezing it to 0.000001K will do more harm than good. From another point of view, it is time for people to realize that there are much more forms of cooling in the field of science and engineering (cooling atoms to absolutely zero, cooling plasmas from destroying the whole research facility, cooling mirrors in high-energy laser facilities, etc.), most of which really have nothing to do with processors. It is naive to think otherwise.
Get a life, people. I mean a real one. If you do not wish to do that, maybe you should spend some of the time you saved and go study.
Maybe not new, but news (Score:2)
If you must do one of these "that's not new" posts, at least include something of substance about the old research.
DECADE OLD TECHNOLOGY!!! (Score:1)
---
pb Reply or e-mail; don't vaguely moderate [152.7.41.11].
What's Interesting to Geeks (Score:1)
A) a rehashed (but still interesting) story on supercooling tiny amounts of matter and
B) a story on a ~$180 processor that you can slap in a mobo and overclock to a gigahertz
the obvious geek-appealing story didn't even get mentioned by "News for Nerds". (Or is this "Old News for Quantum Physicists"?)
Call me silly and slap me Sally. Or the other way around, I don't know...
telnet://bbs.ufies.org
Trade Wars Lives
Warning. This is a troll! (Score:1)
If you want something as little bit newer, then you can try http://www.newscientist.co m/features/features_22341.html [newscientist.com] for something to really argue about.
YOUR BODY is teeming with quantum computers. Marching along your DNA and floating around your cells, several hundred million of these minuscule devices...
Sound interesting? Feel free to go beserk.
You might be strangling my chicken, but you don't want to know what I'm doing to your hampster.
Re:Cooling ATOMS not processors (Score:3)
Not so (I was surprised as well). At Los Alamos they have used optical refigeration to cool a lump of Ytterbium (4mm x 4mm x 7mm - so it is a visible lump) by 0.3K (not to, by). Details here [lanl.gov]. Only one laser required too. But yes, the story was clueless.
Cooling atoms, the easy way (Score:2)
Experimental Aspects of BEC [otago.ac.nz]
This is actually a gratuitous plug for my groups homepage, but its worth a look.
Re:Invariance of velocity? (Score:1)
After 95 years, there is very little evidence that anything in the Special Theory of Relativity was wrong. In the General Theory of Relativity, there may be some dispute on constants and other possible terms, but it also seems correct.
Yes, this was offtopic. But the topic is stupid.
Re:uses of laser cooling. (Score:3)
How it works (Score:1)
If you want to go colder than that, you have to put the atoms is a little magnetic cup, and then slowly make the bottom of the cup come up as the top expands. This will allow any atoms with larger kinetic energies to escape, cooling the group even more. Once you've done this enough, you'll have a bose-einstein condensate. These are really, REALLY cool (pun intended). You've basically cooled the atoms to the point where the de Broglie wavelength becomes large than the interatomic spacing, and all the atoms fall into the ground state, all occupying the same region of space.
By the way, this isn't exactly news: Wieman and Cornell did it in 1995.
Re:Maybe not new, but news (Score:1)
What is with this obsession to overclock? (Score:1)
There are limitations on how well overclocking works and what percent faster real performance it gets you, as well as stability implications.
I'm not against overclocking, but making purchase decisions based on overclockability or having an obsession to see how fast you can get a YYY rated chip to go seems to be the wrong way to go about a computer hobby. I'll bet that the tinkering time to find the "perfect" frequency could be used to pay for a faster rated chip in the first place, well, except for the very recent chips.
Re:A point of ideology? (Score:1)
Really ?????? Since when ??????
Reality check time
People elect governments
Governments, once elected, ignore the people and do their own thing
Unfortunately, the governments have to act through 'government employees' - civil servants and the like. In practice, politicians never understand enough to gontrol these people
In most western democracies, government employees get crap wages, but a job for life. It doesn't encourage the 'brightest and best' to join. Once in, staff tend not to leave
In other words, the 'people' are at least two steps removed from control of anything. Those who can control it are working under a government mandate. Government is often ill-informed, or has an agenda. The government employees are often not the sharpest tools in the box, and sometimes have their own agenda. If my car had steering like 'the people' had control, I'd scrap it and take the bus.
I apologise for this being totally off-topic (lasers aren't mentioned once).
Re:uses of laser cooling. (Score:1)
A simple way to describe an atomic clock is that you set the clock at one point then wait and compare the values a little later, for instance you check your watch against a known standard (say the "town clock") wait for a day and check it again and see if your watch is different from the standard.
In an atomic clock cesium is the standard, the limit on the comparison in the old style atomic clocks is that the cesium is moving very fast so the time between setting and checking your clock is VERY short (microseconds IIRC).
The cesium fountain clock makes the time between setting and checking your clock much longer by laser cooling the atoms first, then throwing them upward in a fountain.
and thus extends the precision of the measurement because you let the two clocks run longer before checking them against one another, seconds instead of microseconds.
Old Quote (Score:2)
Don't remember where I heard that, but I think it is very true. Perhaps Slashdot needs to change it's slogan. "Slashdot: News to Rob. Stuff that matters."
Not old news... (Score:1)
oops.
You've been taken in by a grad students joke! (Score:1)
Whoever orginally posted this link thinking you could cool a CPU with lasers got suckered in by a grad student taking a big poke at geekdom's madness for all things overclocked...and by association that means everyone in this thread talking about laser cooled cpu's got suckered in too...
-jef
Re:Cooling ATOMS not processors (Score:1)
If the cooler could be scaled up, it would take 3 kilowatts to maintain the temperature of a 30 watt processor.
Is temperature a macroscopic or quantum? (Score:1)
I remember getting reamed for this in solid-state thermodynamics. We were discussing how diffusion of atoms occurs in solids and were working on how it could be possible that hotter items have faster diffusion rates than the same thing at cooler temperatures. I spoke of the greater vibrational frequency of an atom at high T would allow briefly greater size "hole" in a lattice if the touching atoms moved apart.
I was "Infomed" that temperature is actually a quantum phenomana and has no bearing on the vibrations of an atom. There was reasoning to support this, but the aftermath of having my entire conceptual view of temperature blown away just left me stunned (and mentally incapable) the rest of the day, and I forgot the reasoning I was given for that factoid.
Is this true, and if so what is the reasoning behind justifying that temp is quantum--and thus not controlling of the atomic vibrational ampletude?
ad infinitum (Score:1)
Re:Cooling ATOMS not processors (Score:2)
Simple Concept (Score:1)
While they're in this small area a laser can be shone at them along this axis. If it is at the right frequency, the atoms will only absorb a photon when they are moving towards the laser source. With the absorbtion of momentum the atoms motion is slowed down still further. (it will reradiate the photon, but in a random direction and the recoil will be absorbed by the magnetic field of the trap.) After absorbing a few photons the atoms' motion along the trap axis has been slowed down to a point where their temperature is getting close to 0K.
However this probably won't gain anyone infamy at overclockers.com [overclockers.com], I doubt the old Celeron 300A likes being put in strong magnetic fields.
Re:Laser cooled CPUs (Score:1)
Re:Invariance of velocity? (Score:1)
Time Standards (Score:1)
About three weeks ago I attended a colloqium given by Dr. William Phillips of NIST (National Institute of Standards and Technology) and the `97 Nobel Laureate in Physics on just this topic. The very reason that NIST researched laser cooling was for making super accurate clocks and I believe there have been prototypes made.
/joeyo
Doppler (Score:1)
Say you have a clump of particles which you want to cool. They will only interact with a specific frequency light. So you fire a laser at then with a frequency slightly lower than that. When a particle happens to be moving away from your light source (or in some lateral direction) there is no interaction BUT when the particle is moving towards the light, the light looks dopler shifted to a slightly higher frequency. And thus there is an interaction and the particle moves off in another direction with a different momentum and kinetic energy. If you have several laser sources all converging on one point you can trap the particles (as the particle begins to move off in another direction, it dopler interacts with another laser). The particles are nearly in one spot and moving very slowly and thus are very cold.
Granted, you have to have the particles slow and well localized to begin with, but you can use liquid nitrogen for that...
/joeyo
Re:IF I EVER... (Score:1)
--
Re:ad infinitum (Score:1)
For example if you set your watch to the proverbial "town clock" then check again in a minute they are not very different and it is hard to measure the difference, however if you wait a month, the differences add up to an easily seen and measured correction to the watch.
In an atomic clock you are measuring the clock of cesium letting your clock run some more and checking the difference (the cesium transition is the "town clock" or more accurately it is used to define the second) and correcting your "watch" so it is again at the proper time (frequency). The reason the fountain clock is more precise is the same reason it is more precise to wait a month to measure the difference on your watch, if you wait to short a time it is very difficult (although not impossible - the regular cesium atomic clock) to measure the change. The fountain clock gives seconds to let the clocks run while the regular atomic clocks only allow microseconds.
There's more involved here but this is a simple explaination, off the top of my head, and only peripherally related to my field of study. There might be a more detailed explaination at the NIST website since thier fountain clock is going online soon or has recently gone on line.
So the direct answer to your argument is that the cesium transition keeps the correct time and to get a very accurate clock we can measure time with we contiually reset our watch to the correct "cesium" time.
Why's it belong on Slashdot NOW, though? (Score:2)
I first heard about this stuff 2 years ago, as an attachment to another story, it was on the Discovery Channel...which either has cool science shows, or really boring home improvement shows, and disgusting nature stuff.
Anyway, the guys were using the cooling lasers, along with a bunch of other duct tape/tin can & string technologies to try and find a new state of matter than Einstein had theorized about, once a substance would get really, really close to absolute zero.
The cooling lasers got the substance really, really cold by bouncing out the molecules that had extra energy, and with a bunch of really complex thrown together hacks, they found a new state of matter, which they called Bowes/Einstein Condensate. (I'm not sure on the spelling of that, but I kind of object to naming a state of matter after yourself. It'd be like calling "gas" the "Dalton State" or something.) The technoloy for this is really old, and therefore may be ready for public use...not. Superconductivity changing any of your daily lives yet? Not mine. I'm still in a subconductive world, baby. A lot of these col technologies just end up not having practical, cost effective uses, and remain just cool sound-bites on a website like this, or on the Discovery Channel. The cost of putting cooling lasers in my computer is still going to be far more expensive than me buying a portable icebox and sticking my computer inside of that for at least the next 2 decades.
On top of that, The Man wants to do everything possible to keep lasers out of the hands of the public. Which is why we can only get those really weenie 3 volt 600 nm laser pointers. The government's just afraid in general of us doing stuff like, getting a bunch of cooling lasers and our Playstation 2s, and taking over Canada or something.
laser fusion revisited? ( nuclear cars ) (Score:1)
Lasers have been used to produce non-continuous hot-fusion by wrapping hydrogen in a glass ball, balancing it in a magnetic confinement field, then zapping it in all diretions with a massive lassor burst ( generated from huge capasitors ). At best, you'd be able to take 10 - 20 of these chambers and run them like a motor engine, so it's not the greatest idea in the world.
Cold fusion.. Basic idea: apply an electric field through heavy water with the use of metalic rods. As the water goes through electrolysis, the positive ions move towards one rod, and the negative the other. The positive side would be the hydrogen ions. They would gather around the rod, slowly crowding each other ( even within the rod itself ).. This crowding supposedly causes extreme density and ultimately mild forms of fusion which heat the water. Best part is that the reaction goes on for a long-long time, though I've heard that the heat produced isn't very much. Also I hear things like how finiky the materials are.. Something to do with left v.s. right sided molecules. And at the very least, the lack of reliable reproducability.
So, here's the real question: If cold fusion ( fusion of two heavy ionized hydrogen atoms ( e.g. P1,N1+,E0 ) can work by merely haveing close proximity, can we duplicate this effect by merely super-cooling hydrogen.
Idea 1: produce a super-solid sphere of hydrogen through lasor and magnetic cooling ( could even be only a couple hundred atoms if that's all that's practical ). If this isn't enough then ( assuming there is some validity to the cold-fusion theory ), apply this to the bare cold-fusion apparatus.
Idea 2: Now that you have an extremely dense hydrogen base, blast it with a hot lasor. This returns to the idea of hot-lasor fusion, except that you're applying a hell of a lot of energy to an extremely solid piece of material. What I'm invisioning is that highly excited hydrogen atoms would be far more likely to collide with intense energy as a solid->gas than as just gas -> gas.
Idea 1 would be cool if it worked, but then again, so would cold fusion.
Idea 2 should definately work ( since it works with hot hydrogen gas ( STP at least ) ). But I believe that you can use a hell of a lot less energy in this reaction than in current systems. I believe that if the cooling effect works well enough to minimize the heat blast energy, then we could even see car sized reactors ( assuming that we don't need magnetic fields ). Basically, you spend some time cooling a hydrogen cloud to a pellet, then apply a capasitive lasor burst to it. It should be on a small enough scale that a small engine block should contain the blast. Hell, we might even be able to mimic a sort of piston gas engine. Eg, 6 cylinders where 4 are charging, 1 is actively fusioning, and a 5'th is discharging.
This is, of course, pure speculation. But it is the job of the dreamers to find uses for technology. Assuming that there is any validity to the idea that super-cooling hydrogen can aid fusion, then it can only help the field.
It's even possible that by super-cooling, the inter-nucleus distances are so small that gravity might actually play the same role that it is assumed to play in our sun.
Course, radiation would play a role, and as far as nuclear engine blocks go, I don't know that we would be able to adequately shield the drivers. At least the polution shouldn't be too bad.
What's different... (Score:1)
Really Hot Chick? (Score:1)
better use a dilution refrigerator (Score:1)
Although the concept exists for decades, it is not something you can buy in every shop at every corner. It is (very, VERY simple) a sophisticated fridge wich uses He as coolingmedium. Temperature range is in the low mK's.
Re:First Ontopic posting.. (Score:1)
===============================================
If ignorance is bliss, wipe the smile off my face
Re:This isn't new... but it is cool (Score:1)
You're right this isn't new, but it is still cool (no pun intended). It is good that this kind of news is being released into somewhat mainstream news services.
I have seen the chamber that the Univ of Conn uses to cool atoms down... it is a lot smaller than I would have thought (about a foot in diameter), but then again they are no where near leading the field in reaching absolute zero, but they contribute. It kinda looked like a spider, I believe (it was close to 3 years ago that I saw it) it had CCD cameras around it so they could see in side. The only other thing I remember is it was silver and very cool looking... unforatunely I didn't learn much about it back then... oh well.
Re:The point is obvious! (Score:1)