Science Scientists create never-before-seen form of matter - Page 3

listopencil · 09-25-2013, 08:56 PM

Scientists create never-before-seen form of matter.

http://phys.org/news/2013-09-scienti...fore-seen.html

Harvard and MIT scientists are challenging the conventional wisdom about light, and they didn't need to go to a galaxy far, far away to do it.

Working with colleagues at the Harvard-MIT Center for Ultracold Atoms, a group led by Harvard Professor of Physics Mikhail Lukin and MIT Professor of Physics Vladan Vuletic have managed to coax photons into binding together to form molecules – a state of matter that, until recently, had been purely theoretical. The work is described in a September 25 paper in Nature.

The discovery, Lukin said, runs contrary to decades of accepted wisdom about the nature of light. Photons have long been described as massless particles which don't interact with each other – shine two laser beams at each other, he said, and they simply pass through one another.

"Photonic molecules," however, behave less like traditional lasers and more like something you might find in science fiction – the light saber.

"Most of the properties of light we know about originate from the fact that photons are massless, and that they do not interact with each other," Lukin said. "What we have done is create a special type of medium in which photons interact with each other so strongly that they begin to act as though they have mass, and they bind together to form molecules. This type of photonic bound state has been discussed theoretically for quite a while, but until now it hadn't been observed.

"It's not an in-apt analogy to compare this to light sabers," Lukin added. "When these photons interact with each other, they're pushing against and deflect each other. The physics of what's happening in these molecules is similar to what we see in the movies."

To get the normally-massless photons to bind to each other, Lukin and colleagues, including Harvard post-doctoral fellow Ofer Fisterberg, former Harvard doctoral student Alexey Gorshkov and MIT graduate students Thibault Peyronel and Qiu Liang couldn't rely on something like the Force – they instead turned to a set of more extreme conditions.

Researchers began by pumped rubidium atoms into a vacuum chamber, then used lasers to cool the cloud of atoms to just a few degrees above absolute zero. Using extremely weak laser pulses, they then fired single photons into the cloud of atoms.

As the photons enter the cloud of cold atoms, Lukin said, its energy excites atoms along its path, causing the photon to slow dramatically. As the photon moves through the cloud, that energy is handed off from atom to atom, and eventually exits the cloud with the photon.

"When the photon exits the medium, its identity is preserved," Lukin said. "It's the same effect we see with refraction of light in a water glass. The light enters the water, it hands off part of its energy to the medium, and inside it exists as light and matter coupled together, but when it exits, it's still light. The process that takes place is the same it's just a bit more extreme – the light is slowed considerably, and a lot more energy is given away than during refraction."

When Lukin and colleagues fired two photons into the cloud, they were surprised to see them exit together, as a single molecule.

The reason they form the never-before-seen molecules?

An effect called a Rydberg blockade, Lukin said, which states that when an atom is excited, nearby atoms cannot be excited to the same degree. In practice, the effect means that as two photons enter the atomic cloud, the first excites an atom, but must move forward before the second photon can excite nearby atoms.

The result, he said, is that the two photons push and pull each other through the cloud as their energy is handed off from one atom to the next.

"It's a photonic interaction that's mediated by the atomic interaction," Lukin said. "That makes these two photons behave like a molecule, and when they exit the medium they're much more likely to do so together than as single photons."

While the effect is unusual, it does have some practical applications as well.

"We do this for fun, and because we're pushing the frontiers of science," Lukin said. "But it feeds into the bigger picture of what we're doing because photons remain the best possible means to carry quantum information. The handicap, though, has been that photons don't interact with each other."

To build a quantum computer, he explained, researchers need to build a system that can preserve quantum information, and process it using quantum logic operations. The challenge, however, is that quantum logic requires interactions between individual quanta so that quantum systems can be switched to perform information processing.

"What we demonstrate with this process allows us to do that," Lukin said. "Before we make a useful, practical quantum switch or photonic logic gate we have to improve the performance, so it's still at the proof-of-concept level, but this is an important step. The physical principles we've established here are important."

The system could even be useful in classical computing, Lukin said, considering the power-dissipation challenges chip-makers now face. A number of companies – including IBM – have worked to develop systems that rely on optical routers that convert light signals into electrical signals, but those systems face their own hurdles.

Lukin also suggested that the system might one day even be used to create complex three-dimensional structures – such as crystals – wholly out of light.

"What it will be useful for we don't know yet, but it's a new state of matter, so we are hopeful that new applications may emerge as we continue to investigate these photonic molecules' properties," he said.

tredadda · 09-25-2013, 10:02 PM

Quote:

Originally Posted by Canofbier

Uhh, he quoted the article that he already posted.

You're suggesting that this research as no "usable" outcome, and I'm saying that this is among the most practical knowledge that there is to be gained.

He did quote the article, you did not even do that. I never suggested it was not useable , just asked how we benefit from this of which you chose at that time not to answer. It's all good though because I did get an answer to the question which was all I was seeking in the first place.

**Canofbier** · 09-25-2013, 10:07 PM

Quote:

Originally Posted by tredadda

He did quote the article, you did not even do that. I never suggested it was not useable , just asked how we benefit from this of which you chose at that time not to answer. It's all good though because I did get an answer to the question which was all I was seeking in the first place.

I didn't quote the article because it was provided in the original post...I imagine that he did so for you because you evidently needed a reminder.

It's a ****ing given that the answer to your question is yet-unknown, and that's what makes this kind of research exciting. Acting as though those kind of questions make you an intellectual is embarrassing.

tredadda · 09-25-2013, 10:18 PM

Quote:

Originally Posted by Canofbier

I didn't quote the article because it was provided in the original post...I imagine that he did so for you because you evidently needed a reminder.

It's a ****ing given that the answer to your question is yet-unknown, and that's what makes this kind of research exciting. Acting as though those kind of questions make you an intellectual is embarrassing.

Then if the answer is unknown, why couldn't you just say that? Who said I was trying to act as an intellectual based off of my questions? I just asked a couple of questions. Unfortunately you are looking way too much into it. Not much I can do about that.

'Hamas' Jenkins · 09-25-2013, 10:22 PM

Quote:

Originally Posted by tredadda

Then if the answer is unknown, why couldn't you just say that? Who said I was trying to act as an intellectual based off of my questions? I just asked a couple of questions. Unfortunately you are looking way too much into it. Not much I can do about that.

You were being sarcastic and anti-intellectual, and it's completely obvious to anyone who read the scare quotes around amazing and the facetious tone of your post.

**Dave Lane** · 09-25-2013, 10:25 PM

Quote:

Originally Posted by 'Hamas' Jenkins

You were being sarcastic and anti-intellectual, and it's completely obvious to anyone who read the scare quotes around amazing and the facetious tone of your post.

Ya think?

tredadda · 09-25-2013, 10:26 PM

Quote:

Originally Posted by 'Hamas' Jenkins

You were being sarcastic and anti-intellectual, and it's completely obvious to anyone who read the scare quotes around amazing and the facetious tone of your post.

You got all that from words I typed? Impressive I guess.

Psyko Tek · 09-25-2013, 10:38 PM

Quote:

Originally Posted by listopencil

P.S.

TL/DR: Super computers based on light will run Sky Net.

WE got light sabers sky net doesn't have a chance

Psyko Tek · 09-25-2013, 10:43 PM

Quote:

Originally Posted by tredadda

How will we as a society be better because of this discovery? How does anyone benefit from this?

jebus crispus,

just stay out of stuff you don't have a clue about
like conversation

WhawhaWhat · 09-25-2013, 11:12 PM

ELI5?

listopencil · 09-25-2013, 11:44 PM

Quote:

Originally Posted by WhawhaWhat

ELI5?

It looks like we can cause an important change in light. This might allow us to control light in a way we haven't been able to before. It would act more like a chunk of stuff that we could make things out of. In a way, it isn't even really light anymore.

Earthling · 09-26-2013, 01:15 AM

Fascinating! What is also cool about this article was the mentioning of cooling atoms with lasers. I've never heard of that but am curious as to how that works.

vailpass · 09-26-2013, 01:18 AM

Quote:

Originally Posted by Psyko Tek

jebus crispus,

just stay out of stuff you don't have a clue about
like conversation

It seems like a relevant question...

dmahurin · 09-26-2013, 01:26 AM

Quote:

Originally Posted by listopencil

It looks like we can cause an important change in light. This might allow us to control light in a way we haven't been able to before. It would act more like a chunk of stuff that we could make things out of. In a way, it isn't even really light anymore.

Put the technology on a spacecraft to affect the light in front of it. If the technology causes light to interact it could cause the light to slow down allowing for the ship to travel faster than light. Time travel? Light speed? Ludicrous speed?

listopencil · 09-26-2013, 01:57 AM

Quote:

Originally Posted by dmahurin

Put the technology on a spacecraft to affect the light in front of it. If the technology causes light to interact it could cause the light to slow down allowing for the ship to travel faster than light. Time travel? Light speed? Ludicrous speed?

Not a change in Light. A change in light.

ChiefRocka · 09-26-2013, 05:48 AM

09-25-2013, 08:56 PM
listopencil Immanentize The Eschaton Join Date: Oct 2002 Location: In Partibus Infidelium Casino cash: $2255880	Scientists create never-before-seen form of matter Scientists create never-before-seen form of matter. http://phys.org/news/2013-09-scienti...fore-seen.html Harvard and MIT scientists are challenging the conventional wisdom about light, and they didn't need to go to a galaxy far, far away to do it. Working with colleagues at the Harvard-MIT Center for Ultracold Atoms, a group led by Harvard Professor of Physics Mikhail Lukin and MIT Professor of Physics Vladan Vuletic have managed to coax photons into binding together to form molecules – a state of matter that, until recently, had been purely theoretical. The work is described in a September 25 paper in Nature. The discovery, Lukin said, runs contrary to decades of accepted wisdom about the nature of light. Photons have long been described as massless particles which don't interact with each other – shine two laser beams at each other, he said, and they simply pass through one another. "Photonic molecules," however, behave less like traditional lasers and more like something you might find in science fiction – the light saber. "Most of the properties of light we know about originate from the fact that photons are massless, and that they do not interact with each other," Lukin said. "What we have done is create a special type of medium in which photons interact with each other so strongly that they begin to act as though they have mass, and they bind together to form molecules. This type of photonic bound state has been discussed theoretically for quite a while, but until now it hadn't been observed. "It's not an in-apt analogy to compare this to light sabers," Lukin added. "When these photons interact with each other, they're pushing against and deflect each other. The physics of what's happening in these molecules is similar to what we see in the movies." To get the normally-massless photons to bind to each other, Lukin and colleagues, including Harvard post-doctoral fellow Ofer Fisterberg, former Harvard doctoral student Alexey Gorshkov and MIT graduate students Thibault Peyronel and Qiu Liang couldn't rely on something like the Force – they instead turned to a set of more extreme conditions. Researchers began by pumped rubidium atoms into a vacuum chamber, then used lasers to cool the cloud of atoms to just a few degrees above absolute zero. Using extremely weak laser pulses, they then fired single photons into the cloud of atoms. As the photons enter the cloud of cold atoms, Lukin said, its energy excites atoms along its path, causing the photon to slow dramatically. As the photon moves through the cloud, that energy is handed off from atom to atom, and eventually exits the cloud with the photon. "When the photon exits the medium, its identity is preserved," Lukin said. "It's the same effect we see with refraction of light in a water glass. The light enters the water, it hands off part of its energy to the medium, and inside it exists as light and matter coupled together, but when it exits, it's still light. The process that takes place is the same it's just a bit more extreme – the light is slowed considerably, and a lot more energy is given away than during refraction." When Lukin and colleagues fired two photons into the cloud, they were surprised to see them exit together, as a single molecule. The reason they form the never-before-seen molecules? An effect called a Rydberg blockade, Lukin said, which states that when an atom is excited, nearby atoms cannot be excited to the same degree. In practice, the effect means that as two photons enter the atomic cloud, the first excites an atom, but must move forward before the second photon can excite nearby atoms. The result, he said, is that the two photons push and pull each other through the cloud as their energy is handed off from one atom to the next. "It's a photonic interaction that's mediated by the atomic interaction," Lukin said. "That makes these two photons behave like a molecule, and when they exit the medium they're much more likely to do so together than as single photons." While the effect is unusual, it does have some practical applications as well. "We do this for fun, and because we're pushing the frontiers of science," Lukin said. "But it feeds into the bigger picture of what we're doing because photons remain the best possible means to carry quantum information. The handicap, though, has been that photons don't interact with each other." To build a quantum computer, he explained, researchers need to build a system that can preserve quantum information, and process it using quantum logic operations. The challenge, however, is that quantum logic requires interactions between individual quanta so that quantum systems can be switched to perform information processing. "What we demonstrate with this process allows us to do that," Lukin said. "Before we make a useful, practical quantum switch or photonic logic gate we have to improve the performance, so it's still at the proof-of-concept level, but this is an important step. The physical principles we've established here are important." The system could even be useful in classical computing, Lukin said, considering the power-dissipation challenges chip-makers now face. A number of companies – including IBM – have worked to develop systems that rely on optical routers that convert light signals into electrical signals, but those systems face their own hurdles. Lukin also suggested that the system might one day even be used to create complex three-dimensional structures – such as crystals – wholly out of light. "What it will be useful for we don't know yet, but it's a new state of matter, so we are hopeful that new applications may emerge as we continue to investigate these photonic molecules' properties," he said.
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09-26-2013, 01:15 AM	#41
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09-26-2013, 05:48 AM	#45
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