The 38mph result was from 11 years ago, the title of this (2007) article is "Light and matter united" and it's far more startling...
> She and her team made a light pulse disappear from one cold cloud then retrieved it from another cloud nearby. In the process, light was converted into matter then back into light.
More accurate, to my layman's interpretation, would be to say that light was converted to information, encoded in existing matter, then converted back to light. Saying it was converted to matter seems to imply that new matter was created in the process which doesn't appear to be the case.
"She and her team made a light pulse disappear from one cold cloud then retrieved it from another cloud nearby. In the process, light was converted into matter then back into light."
When I first read that, the only response I had was "Beam me up Scotty"
I think it was more of a stunned response than anything. Mind = Blown.
Maybe I'm dense, but I don't see how this experiment shows that the original light beam was affected in any way. Seems to me that the original light beam etched information onto the "cold atomic cloud", and then later an entirely new beam of light (with identical properties) was emitted (or reflected) from the laser blast's impact on this "etching".
How can they reach the conclusion that the original light beam itself was altered from this experiment?
They mislabeled the event when they said that the light was "converted" into matter. This is sad because I think many people will miss the greatness of what was really done because of it. A large (long) beam of light (everything about it) was stored in a very small amount of matter, then recreated exactly. It wasn't light like what was there before, diffracted from new light (like a hologram), it was the same light.
Once this becomes practical, we have practically infinite data storage, not to mention the underpinnings of computing with pure light, so perhaps practically infinite computational speed as well.
"then later an entirely new beam of light (with identical properties) "
I think, if you understand quantum physics, it's meaningless to say that it's a "new beam of light with identical properties." If it "has the same properties", then it is the "same beam of light." It doesn't just look the same. It is the same in a physical (and meta-physical?) sense.
Then again, I don't really understand quantum physics, so I might be misunderstanding this. I'm telling you what I picked up from Eliezer Yudkowsky's series on quantum electrodynamics.
What's amazing about this case is that all of the quantum states were maintained as well. The light maintained entanglement with other photons. This is not something that could happen by simply storing information and retrieving it later.
Currently, quantum encryption setups require a fiber optic cable to reach all the way from the sender to the recipient, because repeaters would destroy the entanglement. But with this device, you could store the data in a Bose-Einstein condensate, ship it to the destination, then read the data back out.
<quote>Einstein and just about every other physicist insisted that light travels 186,000 miles a second in free space, and that it can't be speeded-up or slowed down. But in 1998, Hau, for the first time in history, slowed light to 38 miles an hour, about the speed of rush-hour traffic.
<quote>
I wouldn't have been surprised if a newspaper journalist used dramatization that indicated as if Einstein is proven wrong. I didn't expect that kind of dramatization when reporting scientific matters on news.harvard.
Of course, Einstein is still right. All these experiments slow down the speed of light when it's traveling in special matter at special temperatures. Constant speed of light in free space is a necessary condition for Theory of Relativity be correct. If that condition is found to be incorrect, our current understanding of the universe completely goes for a toss;
Indeed. To be even more specific, the reason why it is slowed down is because of absorption and re-emittance of particles of light (photons). If you go down the the extremely small scale, what you will actually see is a photon moving at the speed of light, colliding with an atom, being absorbed by an electron, then re-emitted on the other side. Repeat this process ad nauseam and the constant absorption/re-emittance will slow down the speed of light to a varying degree. Most importantly, however, is that the c is constant in free space.
This reminds me of something that I think I first read about in Michio Kaku's book Physics of the Impossible where a Bose-Einstein condensate was used as a medium for "teleportation". I believe in his book he referred to the experiment referenced here. http://www.physorg.com/news102681027.html
They are careful to note that it is a transmission of information rather than photons. It sounds like this experiment is similar, but I am certainly not qualified to comment authoritatively on that.
It would make sense that teleportation (or perceived teleportation) would be possible from it, since all matter is is stored information. Now the question is if matter is the only way to store information aside from light. If this is so, then if you reduced an object or human to its light representation, you would be able to travel at the speed of light, but no faster, which would be perceived teleportation - I'm assuming teleportation is instantaneous whereas going the speed of light is not. Hopefully no one would slow you down in the meant time.
The article seems very loose with its terminology which makes it really confusing. For example:
> Albert Einstein and just about every other physicist insisted that light travels 186,000 miles a second in free space, and that it can't be speeded-up or slowed down. But in 1998, Hau, for the first time in history, slowed light to 38 miles an hour, about the speed of rush-hour traffic.
Hau did not slow down light in free space so this has nothing to do with Einstein's statement.
What I would like to know is, is underlying fundamental mechanism here similar to or the same as what we know as refraction? From all the descriptions it sounds awfully similar, other than the extreme(!) nature of the slowdown.
Light can NOT be slowed down - at all! What happens with refraction is the light is absorbed by matter, then re-emitted, over and over, which effectively slows it down.
In this case the material that absorbed the light takes a very long time to re-emit it.
[+] [-] timf|16 years ago|reply
> She and her team made a light pulse disappear from one cold cloud then retrieved it from another cloud nearby. In the process, light was converted into matter then back into light.
[+] [-] Bjartr|16 years ago|reply
[+] [-] froo|16 years ago|reply
When I first read that, the only response I had was "Beam me up Scotty"
I think it was more of a stunned response than anything. Mind = Blown.
[+] [-] jpeterson|16 years ago|reply
How can they reach the conclusion that the original light beam itself was altered from this experiment?
[+] [-] noonespecial|16 years ago|reply
Once this becomes practical, we have practically infinite data storage, not to mention the underpinnings of computing with pure light, so perhaps practically infinite computational speed as well.
[+] [-] ljlolel|16 years ago|reply
I think, if you understand quantum physics, it's meaningless to say that it's a "new beam of light with identical properties." If it "has the same properties", then it is the "same beam of light." It doesn't just look the same. It is the same in a physical (and meta-physical?) sense.
Then again, I don't really understand quantum physics, so I might be misunderstanding this. I'm telling you what I picked up from Eliezer Yudkowsky's series on quantum electrodynamics.
Perhaps a physicist can elaborate?
[+] [-] sp332|16 years ago|reply
Currently, quantum encryption setups require a fiber optic cable to reach all the way from the sender to the recipient, because repeaters would destroy the entanglement. But with this device, you could store the data in a Bose-Einstein condensate, ship it to the destination, then read the data back out.
[+] [-] unknown|16 years ago|reply
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[+] [-] nebula|16 years ago|reply
I wouldn't have been surprised if a newspaper journalist used dramatization that indicated as if Einstein is proven wrong. I didn't expect that kind of dramatization when reporting scientific matters on news.harvard.
Of course, Einstein is still right. All these experiments slow down the speed of light when it's traveling in special matter at special temperatures. Constant speed of light in free space is a necessary condition for Theory of Relativity be correct. If that condition is found to be incorrect, our current understanding of the universe completely goes for a toss;
[+] [-] Locke1689|16 years ago|reply
[+] [-] smhinsey|16 years ago|reply
They are careful to note that it is a transmission of information rather than photons. It sounds like this experiment is similar, but I am certainly not qualified to comment authoritatively on that.
[+] [-] ricaurte|16 years ago|reply
[+] [-] zmimon|16 years ago|reply
> Albert Einstein and just about every other physicist insisted that light travels 186,000 miles a second in free space, and that it can't be speeded-up or slowed down. But in 1998, Hau, for the first time in history, slowed light to 38 miles an hour, about the speed of rush-hour traffic.
Hau did not slow down light in free space so this has nothing to do with Einstein's statement.
What I would like to know is, is underlying fundamental mechanism here similar to or the same as what we know as refraction? From all the descriptions it sounds awfully similar, other than the extreme(!) nature of the slowdown.
[+] [-] ars|16 years ago|reply
Light can NOT be slowed down - at all! What happens with refraction is the light is absorbed by matter, then re-emitted, over and over, which effectively slows it down.
In this case the material that absorbed the light takes a very long time to re-emit it.
[+] [-] unknown|16 years ago|reply
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[+] [-] finebanana|16 years ago|reply
[+] [-] tjic|16 years ago|reply
Typical bad science writing.
Mirrors have existed before this year...
[+] [-] eru|16 years ago|reply
[+] [-] diederikm|16 years ago|reply
[+] [-] laut|16 years ago|reply
[+] [-] pra|16 years ago|reply
The experiment and its results are intriguing nevertheless.
[+] [-] cunard-n|16 years ago|reply
[+] [-] rawr|16 years ago|reply
[+] [-] unknown|16 years ago|reply
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