Stopping Light 243
Jon Abbott writes "NASA is reporting that physicists at Harvard University have managed to stop light altogether. The implications of this discovery are rather staggering -- quantum encryption and quantum computers might be just around the corner! " Well, I don't think this will mean any immediate changes - but it is a significant step.
Very, Very Slow Computers (Score:4, Funny)
Yeah...very, very, very slow quantum computers.
;)
-Waldo Jaquith
Thats Nothing! (Score:1)
But only for a second...
Re:Thats Nothing! (Score:2)
Re:Thats Nothing! (Score:1)
Nope, just him and his fingertips [imdb.com].
Applications? (Score:1)
Re:Applications? (Score:1)
You could also do cool shit like make light transistors for quantum computers--they wouldn't get that hot, and they'd move SCREAMINGLY fast.
Stopping light altogether? (Score:2)
Colour me confused.
Re:Stopping light altogether? (Score:2, Informative)
True, but you can contain it. Think of lead-acid batteries, flywheels, or any other energy storage device. The energy becomes somewhat of a potential (although in flywheels the energy is rotational), and can later be turned into useful energy.
Re:Stopping light altogether? (Score:1, Informative)
Re:Stopping light altogether? (Score:3, Informative)
this is what happens (Score:2)
So those atoms go on a higher energy state, as a result of the light they have absorbed.
When they shine another laser on the medium the atoms emit the energy they had previously absorbed, in the form of the same kind of light that came in.
Re:Stopping light altogether? (Score:4, Insightful)
The energy itself I believe is lost, though the waveform of the light, and its pattern is stored in the arrangement/orientation of the atoms. Shining another light into the atoms causes the eminating light to be of the same waveform/pattern.
A better analogy would be intercepting a streaming movie going across your network, waiting a while, and then re-transmitting it. You're not sending the same electrons, but you're sending the same bits.
Re:Stopping light altogether? (Score:1)
Haven't had this discussion in years, so I, too, may be wrong. But IIRC Einstein proved that light is particles that moved like energy (in a waveform).
Re:Stopping light altogether? (Score:2, Informative)
IIRC Einstein proved that light is particles that moved like energy (in a waveform).
Sort of. It was shown that particles behave like waves and vice versa. Thus, since light is a wave it can also be thought of as a particle. We refer to this particle as a photon.
However, it's not a particle in the same way as an electron or a cookie crumb. It has no mass and, thus, exists only in the form of energy.
Re:Stopping light altogether? (Score:3, Interesting)
I can't see what the technical reason is for saying dramatically that this information is "stored" and not "absorbed" - looks like it's just arguing about the spin [
Last year (Score:5, Informative)
Re:Last year (Score:2, Informative)
Nothing new (Score:3, Funny)
The worst part about this story (Score:4, Insightful)
If a photon (light) hits an atom (matter), causing it's electrons to move to a more excited energy level, I defy you to "show me the light". You can't. You can show me a really excited electron, and if you're really clever like these folks at Harvard you can even get that atom to release the exact same light with the exact same waveform, but you haven't stopped light.
It's annoying. How hard is it to say you've "trapped" light?
Re:The worst part about this story (Score:1)
:-p
though I do think that they stoped light with lasers...just can't seem to find the story.
slow glass... (Score:2, Interesting)
This really sounds like a cool way of storing holographic data (which means storing a LOT of information in a small space)
Re:slow glass... (Score:2)
The guy looks at the various pieces that have been out in the woods, etc. for various periods of time.
All the while watching the family of the guy selling the glass- through the front window of their house.
That's the one right?
I would love to know the title and the author. Very, very good story.
.
Re:slow glass... (Score:2)
The various "Slow Glass" stories are a series written by Bob Shaw [vt.edu]
Sig: What Happened To The Censorware Project (censorware.org) [sethf.com]
Re:slow glass... (Score:5, Informative)
Bob Shaw
First came out in '66
Still gives me a lump in my throat just thinking about it.
seems like... (Score:5, Funny)
-m
whoa! (Score:2, Funny)
Re:whoa! (Score:2)
Hey, I just managed to stop light by shining my flashlight at the wall. When I looked on the other side of the wall- NO LIGHT WAS COMING THROUGH!
Maybe now I can... (Score:1)
They did NOT stop light! (Score:4, Insightful)
Re:They did NOT stop light! (Score:1)
Re:They did NOT stop light! (Score:2, Interesting)
Either the photons stopped, or they are floating around in the imaginary universe you live in (just kidding).
Just because you are storing it in a different form doesn't mean you aren't stopping it. Yeah, they may not be the exact same photons, but since photons are massless particles anyways, it's hard to define the Newtonian definition of "stopping" and "going."
Re:They did NOT stop light! (Score:2)
simple answer: electromagnetic waves.
more fundamental answer: energy
What did these scientists do? They directed a light into a cell of rubidium gas. As light goes through this gas it constantly excites atoms and these atoms lose their excited state a moment later and re-emit the pulse that originally excited them. This goes on constantly. So in a sense you can call this normal behaviour of light. This is also why light slows down in any material.
Now what happened was that they froze this process and later could restart it. So in a sense they really did stop light. As light is nothing but energy to begin with it really is not even recording. By recording you're saving information about something. In this case you're storing the actual energy in the excited states of atom. In a sense the light is hibernating..
The button in your hypothetical gadget in this case is nothing but a trigger for a laser beam that causes the atoms to release their stored energy and thus release the "stopped" light.
Re:They did NOT stop light! (Score:2, Insightful)
It's been awhile since my quantum mechanics classes but I believe that storing all the quanum properties of a photon and imprinting them onto another is essintially the same thing as stopping and starting it.
Since a particle or photon is defined as the sum of all of its properties, if you are able to create another instance of the photon that has all of those properties, you've managed to duplicate the photon. It is, for all intents and purposes, the _same_ photon.
Fortunately, no two quantum particles can share the same properties. So as soon as you, form your duplicate, the original ceases to exist. (Technically, the uncertainty princple says that it ceased to be the same particle as soon as you started measuing the properties in the first place.)
Back when I heard about teleportation experiments they were doing just that. A photon's quantum properties were measured and imparted them to another photon some distance away. According the quantum mechanics, the photon teleported.
It sounds like a similar process may be happening here.
Re:They did NOT stop light! (Score:2)
So What is a particle? It's a thing that has specific and unique properties, therfore when two things aquire the exact same properties, they have become one particle! If you make liquid hellium out of a specific isotope, and cool it to a certian temperature, all of the individual atoms aquire the exact same quantum properties and become one particle. That means that we can make a quantum partical that is big enough to physicaly see with the naked eye. One warning, if you ever actualy understand quantum mechanic, your mental state would be indistingishable from insanity.
Fun with photons and your mom's jewellry! (Score:1)
- Jynx
I Own This Patent (Score:1)
Great (Score:5, Funny)
I can just see physicists getting calling people into the lab, turning out the lights and commanding, "Let There Be LIGHT!!!" at every available opportunity
My Town has tons of theses. (Score:5, Funny)
Erm... (Score:2)
Re:Erm... (Score:2)
If the computer uses a mist to store data... (Score:2)
:-)
We have those... (Score:1)
Shouldn't it be pausing light? (Score:1)
More Information (Score:1, Informative)
There's also some news about it here [harvard.edu] at Harvard's site. Also, there's an article here [sciam.com] in Scientific American about this.
Didn't this all happen last year, too? Why is it just news now?
This is old OLD news (Score:2)
This is just old news, The way light was stopped before was they used extreme cold to slow light down until it stopped.
Re:This is old OLD news (Score:2)
Of course, it's going to be even funnier when somebody gives it an 'informative' mod...
This really is vaporware!!! (Score:5, Funny)
So it truly is vaporware!
I wonder what the information density is (Score:2)
Would shaking the storage container make atoms discharge and ruin the whole thing?
OOOoooooo.... (Score:2)
Re:OOOoooooo.... (Score:2, Funny)
lot more than quantum... (Score:1)
Re:lot more than quantum... (Score:1)
You could, of course, read it and re-write it. But, this, too, has problems with it -- you need lasers to do all your dirty work, so you're still limited by the speed of the switching electronics on them. Hmm...
Basically, without some serious work being done, this can't become the mass storage revolution we're all hoping for.
p=mv (Score:3, Interesting)
I just don't believe they stopped the light.
Re:p=mv (Score:2)
Re:p=mv (Score:2)
When we say that light 'slows down' in a material, what is happenning is that the photons are hitting the atoms inside and being absorbed/reemmitted - not always in the same direction, and not instantaneously. Thus, the forward progress of the 'light pulse' is slowed, but not the photons themselves.
Re:p=mv/[1-(v/c)^2]^(1/2) (Score:2)
Einstein was a pretty smart guy...
Mod up AC (Score:2)
Always curious why people post good stuff AC.
The military most likely will use this (Score:1)
Re:The military most likely will use this (Score:1)
Tiwice Before (Score:1, Informative)
Slashdot Jan. 2001 [slashdot.org]
Things are going to change...very soon (Score:2, Insightful)
Discover Magazine (Score:1, Offtopic)
Basically they shoot a laser through a heavy filter, emitting only one photon. The Sender and Receiver exchange pads including what group of spins(Horizontal/Vertical, or the diag's) on each photon contains information. An Evesdropper has a 50% chance of guessing which one, and retransmiting that. The article state that on average 25% of the photons would be incorrect if your conversation was being intercepted due to wrong guesses by the snooper.
Pretty Neat - but they say it'll be at least 10 years for something that consumers can plug into a wall...
Not Exactly... (Score:1)
As for quantum computing this is a big step. They have basically discovered how to imprint something onto atoms, each of which could be a bit (or trit or more, depending on how they implement it) so basically you have an immense ammount of storage in a very small space. Between this and the speed of light that signals would be sent with, you would have a very fast computer with enormous ammounts of memory.
Oh, and as for portable storage, a floppy disk will be able to hold terrabytes of information.
Hypothetically... (Score:1)
Granted the machinary that would pick up a half meter of light from a "bottle of light" would have to do a lot of quick calculation... unless they released it slowly... like their previous experiments to get light to move at a bicycles pace.
The nice thing about light as a storage medium is that the molocules would be infinely close in proximity of one another. If a given the burst technology existed I guess the only thing slowing this down would be the pulse rate that could be achieved from a laser source. I could imagine a line of light, no longer than a football field that contains more information than the current internet.
--Turvey
Great news for quantum computing (Score:5, Informative)
I've noticed a couple of people wondering why this discovery important. Some other people know that it is useful for quantum computing, but they don't know how it would be useful. I'll see if I can help.
The most common way qubits are stored in quantum computers is as spin, which can be thought of as angular momentum, quantum-style. The particle usually used for this task is the electron. So, now we've got the qubit stored as spin, but how do we get the different particle's spin states to interact? If we can't get them to interact, we can't do any computation, so this is a very important question.
The most successful quantum computers (those with 7 qubits) so far use Nuclear Magnetic Resonance (NMR) to make the qubits interact. This has it's problems, and would not be appropriate for a real quantum computer. So, to make a real (ie. Desktop) QC, we need something better.
This story talks about a method of turning information stored in light (as amplitude, IIRC) into spin. This sort of translation is exactly what is needed to make quantum computers work. An example QC could use a bunch of atom's as the memory system, with all of the qubits encoded as spin on the electrons orbiting the atoms. The CPU would be a bunch of optical components (beam splitters, polarizers, mirrors, etc.) that operate kind of like transistors. And the wires would just be fiber optics. Now, this is a little simplified, because it assumes we can make atomic scale optical components, but I am confident that it will happen soon.
Hope this helps some people understand why this is Stuff that matters.
How I learned to love the bomb sorta (Score:3, Informative)
Re:How I learned to love the bomb sorta (Score:2)
Likewise, thinking of it in terms of an atom absorbing the photon is incorrect. It's not the same as dropping a bit of dye into a glass of water, where the water absorbs the photon. It's also not a trap for the photon.
The first thing in understanding quantum mechanics is to first accept that atoms have no real-world counterpart. One cannot imagine an atom or subatomic particles as we imagine physical objects.
Its whacky stuff.
Quantum Computing with Perl (Score:4, Funny)
@quanta=;
foreach $quanta (@quantum)
{
warn "DAMN! destroyed my data by reading it again!\n";
}
Actual quantum Computing with Perl (Score:5, Informative)
Light wasn't stopped. Misleading headline. (Score:2, Interesting)
Sure. (Score:5, Funny)
Headline: Physicists Stop Light
Slashdot: The implications for quantum computing are staggering!
Headline: Transparent Aluminum Invented
Slashdot: The implications for case mods are staggering!
Headline: Secret of Time Travel Discovered
Slashdot: Yay! We don't have to wait 2 years to see the rest of [insert name of trilogy]!
Headline: Scientists Cure Cancer
Slashdot: The implications for quantum computing are staggering!
Headline: Terrorists Nuke South Dakota
Slashdot: The implications for quantum computing are staggering!
Terrorists Nuke South Dakota (Score:3, Funny)
[cf. Small Earthquake in Peru for the humor impaired moderators]
Bah (Score:2)
Re:Bah (Score:2)
Actually there seem to be a lot of Minnesotan
I smell a poll. Is CowboyNeal reading?
RI like this one better... (Score:2)
Slashdot: The implications for case mods are staggering!
-
Not Stopped For So Long... (Score:2, Informative)
but this phase information is quickly lost as the atoms move around in a thermal equilibrium. think about it as sky-writing. the information is written there, but as the particles move around the infomatino is quickly lost.
most of these experiments have been done with UltraCold atom clouds, and the most recent ones (presented at DAMOP last year) were done in Bose-Einstein Condensates.
due to the very short "coherence time", this phenomena is most likely not very useful for quantum computing.
the buzzwords to look for when it comes to quantum computers (i.e. the things most likely to work) are "trapped ions" and "optical lattices". i promise, one of those two will be used in the first functional quantum computer.
muerte
Groundbreaking!! ...or not! (Score:2)
before? [nature.com]
or before? [sciencenews.org]
-D
Improbable (Score:2, Funny)
Damn, it seems we're getting close to the Improbability Drive.
"That's a good name --- ground! I wonder if it will be friends with me?" Thud!
Old hat (Score:5, Informative)
Great Way to Keep the Kids Quiet (Score:2, Funny)
What they didn't explain... (Score:2)
They can absorb light into a container, alter the qubits (how?), and then, how do they send it off again? Opening a quvalve?
Some quEstions require quAnswers.
These bozos need to document a bit more if I'm to build one myself (ok... maybe I'm optimistic).
DMCA Violation? (Score:3, Funny)
In other news, the RIAA filed suit today against God for failing to include Digital Rights Management technology with each atom, in violation of the SSSCA, and for providing an anti-circumvention mechanism within His "Laws of Physics" prodict.
"This will destroy the music industry as we know it!" exclaimed an unnamed music industry representative, "Evil Hackers will be able to use this technology to pirate music off of even protected CD's, because they're all made of atoms!"
God was contacted for comment on these developments, but apparently prefers only to listen, and not reply.
stopping light - so? (Score:2)
On other news (Score:2)
Bose Einstein Condensates (Score:2, Informative)
The article is not very informative about actual physics involved in the newest experiment. However there is a nice description at: http://www.aip.org/physnews/update/521-1.html.
Also there is a an interesting site about Bose-Einstain condensation at
http://www.colorado.edu/physics/2000/bec/index.
with some nifty Java applets
Implications are staggering! (Score:2, Insightful)
(having one of those days when these sorts of breakthroughs seem ever so slightly irrelevant to the future of life on Earth - could you tell?)
Why are these headlines so misleading? (Score:2, Insightful)
There were no photons, people. They didn't stop light. Halted light would mean there are photons in there, moving at exactly zero meters per second. There were no photons left.
Been waiting fro this one a long time (Score:2)
Secure ? Bah... (Score:2)
Am I the only one who thinks it's strange that while we get told about all these fantastic things that can be done which weren't possible a year ago, people still say convincingly that "you can't get the state from the system without leaving finger prints" ?
I'm sure we can't today. And I'm equally sure that someone is going to figure out a way to touch the system so insignificantly that the "reading" cannot be measured.
Like when reading from a hard-drive: Of course the head will alter the state of the platter when passing by - it's just so insignificant that it doesn't matter, and it would probably be hard to measure if anybody tried.
While this is fascinating and all, I just don't buy into the "can't cheat with this one". Many years ago, everyone agreed that you couldn't split an aton - which was natural, because "the atom" itself was a relatively new idea in itself at that time.
I find it hard to believe that the progress stops here.
They need to apply this to windows ... (Score:2)
They stopped light? (Score:2)
Re:What's with the throwaway lines? (Score:2)
What's worse is that he removed the end of my story submission to make room for the quip. FWIW, this is how the original story submission went:
Jon Abbott writes "NASA is reporting that physicists at Harvard University have managed to stop light altogether . The implications of this discovery are rather staggering -- quantum encryption and quantum computers might be just around the corner! <coffee-talk>Discuss.</coffee-talk>"
Re:What's with the throwaway lines? (Score:2)
It's not a throwaway line. (Score:3, Interesting)
He means that it won't mean any significant changes in how we build computers--that is, quantum comptuers are still a ways away. But it is a VERY significant step. If you read the article, they explain how they stopped a laser beam and turned it into information, stored in the up-and-down patterns of the vapor's atom's spin axes.
I mean, you don't have to be a scientist to imagine the possibilities of a vaporous hard drive, with a huge capacity, that gets written to by a laser that changes the state of the atoms within. Drool...
And the best part is no more annoying spinning noise!
Re:It's not a throwaway line. (Score:2)
Re:It's not a throwaway line. (Score:2)
How would you know which atoms hold which data if the particles in the vapor are floating around, mixing with each other?
Beats me. All I know is that the article said that they shone a laser into the vapor, the beam got converted into information stored in the atom's spin axes, and they later used this information to shoot another laser beam with identitcal qualities, effectively pausing a beam of light. HOW they did it is way beyond me. As far as I know, it was magic, and anyone who uses a computer with that technology will have to make an Intelligence check every time they boot up and look at pr0n. But then again, we already do that anyway (and fail)...
Re:Liar! (Score:2, Informative)
Re:Implications for Solar Power (Score:2)
Re:An AWESOME Weapon..... (Score:4, Informative)
Assume you make an incredibly good mirror: it's 99.999999% reflective. (How you're going to manage to do this while still pumping light in from the outside is unclear- 1/2 silvered mirrors are exactly that.) No mirror is even close to this value, BTW- the best around can do about 99.99% or so.
Assume you have a 1 m diameter ball. Light travels 300,000 km/sec: 3e8 m/s. Thus, you get 3e8 collisions with the mirror every second. Total saved light= 0.99999999^3e8 ~= 0.05. In other words, after 1 second only 5% of the light remains.
"Photon torpedoes" supposedly use matter-antimatter as a power source: pure mass-> energy conversion- why bother with light at all?
Eric
Re:Stopping or Changing the SPEED of light (Score:2)
Light isn't 'stopped' in the sense that it hangs there waiting for something to happen (which doesn't make sense if my (limited) understanding of physics is even close to correct), it's simply absorbed into another particle then that particle emits light some indeterminate time later.
btw. Not all galaxies have a red shift. Andromeda has a blue shift (it's coming towards us apparently).