Slashdot Mirror
Repulsive Force Discovered In Light
Aurispector writes in with news that the Yale team that recently discovered an attractive force between two light beams in waveguides has now found a corresponding repulsive force. "'This completes the picture,' [team lead Hong] Tang said. 'We've shown that this is indeed a bipolar light force with both an attractive and repulsive component.' The attractive and repulsive light forces Tang's team discovered are separate from the force created by light's radiation pressure, which pushes against an object as light shines on it. Instead, they push out or pull in sideways from the direction the light travels. Previously, the engineers used the attractive force they discovered to move components on the silicon chip in one direction, such as pulling on a nanoscale switch to open it, but were unable to push it in the opposite direction. Using both forces means they can now have complete control and can manipulate components in both directions. 'We've demonstrated that these are tunable forces we can engineer,' Tang said."
Sweet! Next up, how lightsabers don't work.
Ahhh finally a scientific explanation of why girls are repulsed by me! Its not my lude jokes... its light!
Just like my ex-girlfriend!
Dark Reflection
is for an alcoholic millionaire to cram it into a suit of armor!
That which does not kill us makes us... st
... an explanation as to why so many WoW geeks shriek when they leave their parents'.... errrmmm.... their basements during the day.
If you aren't suspicious of your government's actions, you aren't doing your job as a responsible citizen.
"Repulsive Force Discovered In Light"--well DUH. Anyone who's ever been in a strip club at closing time has witnessed this phenomenon.
Dear Slashdot: next time you want to mess with the site, add a rich-text editor for comments.
Huh, I had always wondered how to resolve conservation of light's angular momentum during destructive interference of collinear laser pulses consisting of phtons of the same "handedness." I wonder if this can be used to explain that.
Anything, as long as you divert enough power to the deflector dish.
While discovering new properties of old phenomena is interesting,
does anyone ever question the 'bravado' of the wording of such
discoveries?
Does it inhibit later discoveries, in creating artificial limitations
through language and subsequently expectation?
If you're interested in facts I'll tell you what they are and I'll give you sources - Chomsky on The Big Idea
What the crap is an article about a newly found force that doesn't explain at least a theory as to the source of the force? Is it magnetic?
Possibly, but this looks like the effect of light beams interacting inside of a target dialectric combined with the differences in light's angular momentum at the different speeds of c inside and outside the target. Aside from also cooking whatever you wanted to tractor, you might be able to accomplish this with very powerful laser pulses and "cloaking" metamaterials. Since the metamaterials bend the relevent light frequencey around a target you may be able to exert the force on the material, use a vastly powerful laser pulse, and not cook the target. This could impart enough force to be useful and could be used to maintain a cloud of such objects over vast distances using a web of laser pulses pushing and pulling the disparate objects into a desired position. Kind of a neat idea and a good intuitive leap to suggest tractor beams
http://www.msnbc.msn.com/id/12961080/
Now emits 100% attractive light. That's twice as much as the next leading brand!
So Earth finally discovers the repulsive force from the ninth light ray that they've known about on the dying planet of Barsoom for millennia. Does that mean that soon we can have navies of huge floating ships like the Kingdom of Helium does? Or that soon we'll be able to see the two colors they know about on Barsoom that we've never seen on Earth?
I already knew that light repelled me.
This was previously demonstrated by cockroaches.
Facts take all of the premium out of arm waving - T. Reynolds
As I understand it, current thinking is that light bends because of gravity, and this is how distant planets and other distant objects are found.
Could it be that it is, instead, is just light being pulled or pushed against something that is being observed, rather than an observation of the gravity that the body has?
The next effect is the same I guess.
In my next incarnation, I hope to come back as a code monkey.
*kzzzt* ...and are suddenly silenced.
return $sig;
Now, data (or Data) can join the dark side, and display a tension-deficit disorder
Previously: "Linux... Toward the Sunrise..." Now: "Linux... Toward the-- No, now, part of Every Sunrise"
There are a lot of jokes as replies, I assume partially because the summary sets them up so well and partially because it is rather dense subject matter. But doesn't this stuff excite you? Years ago a friend and I used to talk about how there should be a way to make computers out of light and we should just try for that, because, well, there isn't much faster. Articles like this mean its closer to reality. Even if it never happens in my life time it still excites me to know we are headed there.
I am sure some physicist is now going to tell me how it's actually better to use some other quantum something for computing and how I don't understand light and subatomic particles/waves/strings/finnegans. I know I don't. I just like the idea of light computers.
In this case, the fundamental reality is, of course, that each photon splits up at the grating and its wave function takes all paths- interfering with itself everywhere in space. When the photon is discovered hitting a screen, it will strike in a place that reveals the least amount of information about the path it actually took, and there will be many such places, called "interference maxima". (It probably won't land in a place that makes it obvious how it got there- such places are interference minima.)
The Casimir force is another "force" like this. Underneath it's still quantum electrodynamics.
If you find this stuff interesting you should read Feynman's QED... basically Quantum Electrodynamics For Dummies. What you'll find is interesting:
These guys are sending beams of IR photons down a channel that is 220nm x 220nm, smaller than their wavelength. So transverse wave motion isn't a consideration at all... the light can barely fit in there and its wavefunction inside has no longitudinal component. I think it can be totally described with two scalar functions along the waveguide. The photons have apparently been through a beamsplitter or something and are being recombined out of phase. It's too bad the article doesn't provide any further details on how the photons were polarized (circular, linear, what?) or how the quantum interference between the two photon states results in transverse forces on the waveguide.
Ugh. That is so digusting.