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Scientists Freeze Pulse Of Light
Smitty825 writes "After slowing down light to slow speeds, scientists at Harvard University have been able to stop light for a very brief period of time without destroying its energy. The article explains how it is different from this previous light-stopping science story - this will hopefully help the development of quantum computers and ways to communicate over long distances without being eavesdropped on."
Now if they could only figure out how to stop SPAM
Imagine going out to a club and getting a frozen "light cube" in your drink which releases a stream of photons as it melts.
Could bring a whole new dimesnion to the humble Tequila Sunrise huh?
A little planning goes a long way...
Makes me think of a physics joke.
Q: What is the difference between stopped light and darkness?
A: You know where darkness is.
The article mentions clearly:
"We have succeeded in holding a light pulse still without taking all the energy away from it," said Mikhail D. Lukin, a Harvard physicist.
This is somehow different from "...without destroying its energy." like it is stated in the posting. Maybe a subtle detail, but not quite the same.
However, a briliant achievement. Kuddos.
Could "Slow Glass" be coming? Bob Shaw wrote about glass that could slow down light so that it took years to pass through and the effects it had on society in his 1972 book Other Days, Other Eyes. Anyone interested in this stuff should hunt down a copy.
Like I did here.
More detailed articles about the research can be found here or here.
Larkin's article itself is here.
Any physics nerds want to explain it to us?
Here's a quote from Terry Pratchett you might like:
"Light thinks it travels faster than anything but it is wrong. No matter how fast light travels it finds the darkness has always got there first, and is waiting for it."
Why were there no pictures of this stopped light? .. oh wait
Officer: "Do you know how fast you were going?"
Heisenberg: "No, but I know exactly where I am!"
paintball
I once read an SF short story that featured windowpanes which light took decades to pass through - thereby letting you look at the past.
The story included the poignant scene of the protagonist looking out at his wife and child playing in the garden - but they had died 15 years earlier. The character used to hang around near the windows, hoping for glimpses of his dead wife, because he, of course, had no control over when he saw her; the windows would "replay the past" in strict linear sequence.
Does anyone know the name & author of the story?
In the story, the windowpanes were made of optical fibre nanotubes that were so tightly coiled up in the windows that the windows could accomodate tubes a few light-years long.
This research suggests more feasibly ways of doing this, though.
Light doesn't actually have "color". Color is our perception of the wavelength of the light. There's another article on BBC that explains the experiment in greater detail. Essentially, they didn't actually freeze the photons, ie. made them stop moving, but used a different method to make the photons bounce back and forth in place. So the "color" should have remained the same.
I am just building my reasoning backwards. To understand what happens to the Photon when it stops, let's first see what happens to the photon when it moves at - well - the speed of light.
From the quickest reference I could dig thru http://www.wired.com/wired/archive/6.07/es_warp.ht ml?pg=3&topic=
So, the faster the photon moves the slower the clocks would appear to move. Then, I guess, the slower the Photon moves the faster the clock would appear to move. And when the photon STOPS, the clock must be moving INSANELY FAST. So how could it be a very brief period of time ? .. I think it is a very very very long period of time.
Guess, it all depends on which perspective you are looking at, and how you are measuring time ...
To see a world in a grain of sand, and then to step back and see the beach where the sand lies
That may be how traditional optical communications works. Quantum crypto, otoh, relies on the light being put in a certain polarization state by the sender. It's designed so that a stream of single photons go from sender to receiver; there can be no equipment in-between. If an intermediary views this photon en-route, it disturbs the polarization seen by the receiver. Because of the way the sender and receiver can agree on which photons were correctly measured, any aberrations (intercepted photons) are discarded. The most you can hope for is a denial-of-service.
Here's a better explanation than I can muster.
"I assumed blithely that there were no elves out there in the darkness"
We have the technology to create a lightsaber. I know what I'm asking Santa for Christmas now.
I think you're missing the point.
These experiments are all a stepping stone towards genuine quantum communication. Previous experiment such as those in Paris (by firing rhubidium through a photon of light)showed that scientists can no measure certain properties of light without destroying the photon, and then re-measure it. The problem was that for quantum communication, you need to disentangle 2 separate photons from an entangled state so that any change you make to one makes ann instantaneous change to the other, it's twin if you like and that can be done it seems. But, keeping the light fixed in a certain place is one of the tricky parts. If they ever succeed at refing these crystals to the extent that a photon can be kept in a deterministic state, then all you need is 2 of these crystals - you can imagine them being placed at opposite ends of our solar system, each crystal containing your premade entangled photon bouncing back and forth, with the crystal itself locked in some kind of black box (cavity).
Presumablt the crystals would have small atomic/sub/atomic sized pin holes to fire the rhubidium or other material through one of the crystals. The the phase shif of the rhubidium caused by this firing also occurs at the other photon (because they are entangled). Then when you measure the phase shift of the second crystal, the difference is twice as great (i.e. the first phase shift plus the second phase shift0 - hence you know at the other end of the solar system, that it was fired. Now all you need is a model, to measure
according to time, t. For example, one crystal could measure every odd microsecond, the other at every even microsecond.
Now you have a unary turing machine, communicating between the stars!!!.
What's wrong with 'Does this smell like chloroform to you?'
As for the frozen light, I'm thinking this will herald a new line in novelty items of the type sold at Spencer Gifts, only to be shoved in a cupboard two days later and never seen again.
Sorry friend, but he is correct and you are wrong.
He stated the 'color' of our photo receptors. Although our photo receptors pick up C, Y, and M -- it is because their colors (as he said) are R, G, and B.
ie: the Red Photoreceptor reflects RED, that is why it is a red colored photoreceptor. Since it reflects RED, it picks up BLUE and GREEN, which make one of the (secondary) colors you mentioned.
You are also wrong saying that RGB is used for pigment. Pigment gets its color by absorbing color, and you see what is reflected. RGB is used for TVs and Monitors where there is a direct source of light.
Cheers!