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Harvard Physicists Make Light Dance
tetrikphimvin and others clued us to the latest work by Harvard's Lene Vestergaard Hau, being published today in the journal Nature. The NYTimes has a good layman's overview of how Hau's team encoded a light beam in a clump of atoms and later reconstituted it elsewhere. The Harvard Gazette offers additional details, a photo, and video links.
Ok, but next time I lead...
If you slow light down wouldnt that also effect the rate of time that the photon experience.
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are you going faster than the speed of light? How does this jibe with relativity?
Stop playing Dance Dance Revolution and get back to work! There's nothing in the research contract about getting physical on the job!
Meanwhile, in Russia, light makes physicists dance.
Hey don't blame me, IANAB
It's called acid maaaaaan. The lights were dancing, the reds tasted soooo good. Purple had a funky smell to it though...
"He uses statistics as a drunken man uses lampposts...for support rather than illumination." - Andrew Lang
Sounds a whole lot like particle entanglement. Any comments with respect to that?
Hope it wasn't the electric slide. ;)
Head asplodes...
No folly is more costly than the folly of intolerant idealism. - Winston Churchill
And I am stumbling over how slowing light down by such a relatively large degree would end up with a reasonably valuable increase of calculation speed. We don't need to slow down electricity to work with it.
Of course, I can comprehend how it may enable physicists to arrive at similar results with less exotic materials and temperatures. Wish I could think of solutions myself. (just a little intelligence envy...)
Semi-automatic amateur armchair Australian philosopher; conjecture ready at any moment...
I don't understand all of the technical aspects. But could this be the method of bending light around an object to create a cloak of invisibility? There was some talk a few months back about making light bend around objects and re-appear on the other side thus rendering them invisible if you may recall. Looks like this may be a possibility soon and the only question left now is what to do with my super-evil invisibility powers!
This is about the dumbest "theory" I've ever heard. The fourth dimension is "expanding?" As in, from one moment in time to another, it's getting bigger? Wait a second, did I just say "moment in TIME?" So you're defining time in terms of an expansion over TIME? You are stupid.
it will do the Macarena, and the universe will suddenly stop expanding and collapse in on the dancing light faster than, er...light.
Though the Nature newsbrief doesn't mention her, the lead author and the main experimentalist was Naomi Ginsberg, a PhD student in Lene Hau's lab. You can read the article abstract on Nature's website: http://www.nature.com/doifinder/10.1038/nature0549 3
The AFP wire item also gives credit where credit is due:
http://www.cosmosmagazine.com/node/1028
Ah come on, all you need is metatime. And then metametatime. And then ....
Hee hee... that's funny, despite the fact that it's wrong.
Frame of reference is an idea that actually had it's beginnings in Einstein's work. The idea being, can a person determine the absolute velocity of [something]. For example, from the frame of reference of the earth, my car goes 65 miles per hour. From the frame of reference of the sun, my car goes 2.9 km/s (because the earth moves that fast around the sun.
Why is this important? Well, Einstein used this to question why the speed of light seemed constant despite your frame of reference. On a ball of rock orbiting the sun at 2.9 km/s, the speed of light is c. On the surface of the sun (which has no orbital velocity in comparison to the earth), the speed of light is still c. From the frame of reference of the center of the galaxy (where the sun has extremely high relative velocity - which I'm too lazy to look up) the speed of light is still c.
Which means that, either the speed of light somehow knows how fast you are going and adjusts itself (which is, of course, retarded) or there is something about spacetime that makes it seem that way. Hence the general theory of relativity was developed to explain it. (Which, in case you are curious, states that the ruler that you are using lenghtens or shortens depending on your "frame of reference")
So, it's actually quite important.
And as soon as you view the data it disappears? I'm sure the *AAs and various three-letter-acronym government organizations will love this, but I wouldn't want to save my own data this way.
With any luck, they can put these atoms in a phial to be released when all other lights are dark. I know someone who could really use it.
Any technology sufficiently advanced is indistinguishable from magic.
If you don't know where you are going, you will wind up somewhere else.
No this is more like an optical data latch if you must reach for analogies.
Where do you get CMOS? Do you see any complimentary metal oxide semiconductors in there? And it behaves nothing like a transistor.
I don't need no instructions to know how to rock!!!!
You're assuming that the 4th dimension is time. Nobody has ever said that was the case, although many people have ASSUMED it to be true. The 4th dimension is a direction, much like up, down, or sideways, but is orthogonal to all three. See here for a description.
I'd mod your troll to something else if it wasn't for the "You are stupid" comment at the end. It's interesting, though, to see such careless disregard for other people's feelings.
Have you ever considered piracy? You'd make a wonderful Dread Pirate Roberts.
Though this closely resembles copy+paste spam, the theory does sound intriguing, and definitely is one I've never heard of. Any actual physics majors here willing to throw their 2 cents at debunking it?
You're assuming that the 4th dimension is time. Nobody has ever said that was the case, although many people have ASSUMED it to be true. The 4th dimension is a direction, much like up, down, or sideways, but is orthogonal to all three. See here for a description.
It has nothing to do with what the fourth dimension IS. The problem is the use of the word "expanding." For something to expand, it must change size between two points in TIME. So the entire concept of expansion is ROOTED in time and cannot be used to EXPLAIN time.
If the expansion is not across time (in other words, we are talking about dx/dw where w is not in temporal units) then what exactly IS it across? We have to continue to postulate dimensions in order to define the term "expansion."
It's interesting, though, to see such careless disregard for other people's feelings.
I called him stupid for spamming Slashdot when he could have just posted a link, not because of his theoretical aspirations.
My hamster, Melvin, is slow when he's cold and "stops" light. Coincidentally, he can then "release" the light when hit with a laser.
It's only a model.
Anybody notice the 2001 date on the webpage? Is that an error at Harvard or is this a really old article?
Sounds like a good way to store "one time play" holographs (or even one time holographic passwords).
Forget thrust, drag, lift and weight. Airplanes fly because of money.
Seriously. I'd like to see a video of an hour-long full-body orgasm.....
-Clio
Karma: Bad (mostly from not giving a fuck)
Blog: http://clintjcl.wordpress.com
heh
-Clio
Karma: Bad (mostly from not giving a fuck)
Blog: http://clintjcl.wordpress.com
There, fixed it for ya. You were too smug to notice that you put your words into his mouth, and then accused him of making a flawed definition.
If you can define the term "expansion" without referring to temporality, I'll concede.
I've always liked the word Xenon. In fact, I thought I made it up around age 5 and later discovered it was an actual element, but maybe I subconciously heard it. Anyway -- good to know. I'll keep my eye out for xenon in dark alleys. heh.
-Clio
Karma: Bad (mostly from not giving a fuck)
Blog: http://clintjcl.wordpress.com
The Ageless Photon
A photon does not age. No time passes for a photon. This is because although a photon travels with the velocity c, it stays at the exact same place in the fourth dimension as it surfs the expanding fourth dimension. How else, other than with a moving fourth dimension, can we explain that the only way to stay stationary in the fourth dimension is to move at the velocity of c relative to the three spatial dimensions? And how else, but with a moving fourth dimension, can we explain that any object stationary in the three spatial dimensions is moving with a velocity of c relative to the fourth dimension?
Time is an Emergent Phenomena of Moving Dimensions--It is Not a Dimension
Einstein's, Penrose's (and many leading physicist's) mistaken view of "the future being out there" in a block universe arises because physicists misleadingly label "time" the fourth dimension, thus implying that just as we can move anywhere in the three spatial dimensions, such as up and down and back again, so too can we move anywhere in the time dimension, to the past, the future, and back again, implying that both the past and future must exist, as sure as New York and Los Angeles.
But time is not so much the fourth dimension as it is an emergent phenomena that arises because a fourth dimension is expanding at the rate of c relative to the three spatial dimensions in a spherically symmetric manner in units of the Planck length.
Einstein was Right:
Einstein proclaimed that all objects travel through space-time at c. Even though we perceive a ruler along the x axis to be stationary, it is yet traveling through space-time at the fixed speed of c, implying that it is moving through time at the rate of c. Rotate it towards the y axis, and its projection upon the x axis shortens, yet it still appears to be stationary, and it is still traveling through space-time at the rate of c, meaning that it is still traveling at the rate of c through time, as it is stationary in space. Rotate it into the time dimension instead of into the y dimension, and its projection along the x axis still shortens (Lorentz contraction), but now it begins to move through the three spatial dimensions, while maintaining the fixed speed of c through space-time. Again, we see it propagate faster through the three spatial dimensions as it is rotated into the fourth "time" dimension (via a boost) because the fourth dimension is moving relative to the three spatial dimensions.
Simply put, it is not possible to rotate an object into the fourth "time" dimension without that object's velocity through the three stationary dimensions changing. Thus the time dimension itself must be expanding relative to the three spatial dimensions. Another way of looking at this is asking, "Why must something always gain a greater velocity through space when it is rotated into the fourth "time" dimension?" If someone can conduct a Lorentz transformation on a ruler, and rotate it into the fourth dimension without its velocity augmenting through the three spatial dimensions, I would very much like to hear about it.
Moving Dimensions Theory explains a lot of physics without growing government bureaucracies, and thus it is generally deemed as unworthy by tenured String Theorists and other government officials.
But MDT explains:
The Collapse of the Wave Function:
The collapse of the wave function is also known as an irreversible process, or a measurement, akin to a photon blackening a grain in photographic film, or a photon being measured in front of one slit or the other in a double-slit experiment, whereupon the interference pattern disappears because the slit is ascertained, the wave has collapsed, and the matter exhibits particulate behavior. Before it was measured, the photon expanded through space as a spherically-symmetric wave front, as it was matter surfing the expanding fourth dimension, which is expanding through space in a spherically-symmetric manner. Until the photon interacts with matter, or a measuremen
As Brian Greene points out in the Appendix to Chapter 2 of The Elegant Universe, we note that from the space-time position 4-vector x=(ct,x1,x2,x3), we can create the velocity 4-vector u=dx/d(tau), where tau is the proper time defined by d(tau)^2=dt^2-c^-2(dx1^2+dx2^2+dx3^2). Then the "speed through space-time" is the magnitude of the 4-vector u, ((c^2dt^2-dx^2)/(dt^2-c^-2dx^2))^(1/2), which is identically the speed of light c. Now, we can rearrange the equation c^2(dt/d(tau))^2-(dx/d(tau))^2=c^2 to be c^2(d(tau)/dt))^2+(dx/d(tau))^2=c^2. This shows that an increase of an object's speed through space, (dx/d(tau))^2)^(1/2)= dx/d(tau) must be accompanied by a decrease in d(tau)/dt which is the object's speed through time, which also may be considered the rate at which time elapses on its own clock d(tau) or the proper time, as compared with that on our stationary clock dt."
Yawn. This is undergraduate level. Notice that the argument relies on the concept of "tau" which is the "proper time." So we are describing measured time in terms of proper time. Who cares -- Einstein figured this out almost a century ago. Just because Greene writes it in a book doesn't make it new, and it is not saying what you seem to think it's saying. Now you get to explain what "tau" is, in terms that do not include the notion of time. Good luck.
Consider a 4th dimension expanding relative to the three spatial dimensions in units of the Planck length at the rate of c.
And then you use the word "rate" which blows the whole damn thing out of the water. Please stop spamming us with irrelevant math.
I'd mod your troll to something else if it wasn't for the "You are stupid" comment at the end. It's interesting, though, to see such careless disregard for other people's feelings.
As a followup to this comment, the continued spamming behavior of this user (who has now posted the same crap about 5 times) coupled with his inability to grasp the concept that a "expansion" necessarily must be described in terms of a TEMPORAL VARIABLE, puts him firmly in the set of people who's feelings I feel justified in disregarding.
Okay, I was initially going to bat for you(not because of your copy/pasting, but because the theory sounded interesting) but now this is entirely stupid and avoid the actual question asked: If the time dimension is expanding, under what metric? As expansion in space-time is scale relative to time, how can the space dimension expand any if time is no longer a factor(being time itself as it were)?
If asked a question, you do not post an unformatted clipboard copy of the entire FAQ page. That just shows that you are completely clueless on the subject and are letting the linked-to page do the arguing for you(and badly).
Well, to be fair, it's entirely possible that this fourth dimension is expanding relative to some other metric which is not temporal, but that merely shifts the mystery to this new dimension. What point is there in "explaining" the flow of time if we can only do so in terms of another concept which is equally mysterious?
Unfortunately, the poor guy has been misguided by the "Whoo, mystical" style of Greene's writing. It's a good style if you want to sell books, I guess... Greene is talking about basic concepts in Minkowski space, none of which are particularly hard to deal with, and none of which address the true nature of time.
So, for a photon, there is no time (the gamma becomes infinite). Big deal. It's weird, but accept it and move on, so you can do some actual physics.
I just ran out of mod points, but I definitely found this informative.
If you can read this sig, you're too close.
Harvard Physicists Make Light Dance
It's about time those stuffed-shirts had some fun. And being it's just a "light" dance, they won't even break a sweat.
Have you read my journal today?
turn up the beegees again :))
I know you're out there. I can feel you now. I know that you're afraid. You're afraid of us. You're afraid of change.