 |
| View previous topic :: View next topic |
| Author |
Message |
MercuryCrest The Severed Head Of A
Great Old One Joined: 24 Mar 2003 Total posts: 753 Location: Floating down the Ganges Age: 33 Gender: Male |
 Posted: 29-09-2013 20:23 Post subject: Scientists create new form of matter... |
 |
|
|
No one's posted this here yet:
http://phys.org/news/2013-09-scientists-never-before-seen.html
I'm on the fence about quoting the whole article, and I don't think it's likely to disappear, but as far as I know, this is standard....
| Quote: | 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. |
If mods would like, feel free to remove the quoted part. |
|
| Back to top |
|
 |
| rynner2 What a Cad!
Great Old One Joined: 13 Dec 2008 Total posts: 21365 Location: Under the moon Gender: Male |
|
| Back to top |
|
|
| Pietro_Mercurios Heuristically Challenged
Gender: Unknown |
| Posted: 29-09-2013 21:37 Post subject: |
|
|
|
I've already posted this story, over on the Star Wars thread.
I blame quantum entanglement.  |
|
| Back to top |
|
|
| MercuryCrest The Severed Head Of A
Great Old One Joined: 24 Mar 2003 Total posts: 753 Location: Floating down the Ganges Age: 33 Gender: Male |
| Posted: 30-09-2013 07:48 Post subject: |
|
|
|
I honestly never check "Fortean Culture" and, let's be honest, the whole 'lightsaber' bit is clearly click-bait (don't think I don't want one of me own....).
That being said, feel free to merge or delete this, mods.... |
|
| Back to top |
|
|
| Anome_ Faceless Man
Great Old One Joined: 23 May 2002 Total posts: 5377 Location: Left, and to the back. Age: 45 Gender: Male |
| Posted: 30-09-2013 07:56 Post subject: |
|
|
|
I think it's valid to discuss this in New Science. Especially as the whole thing seems a bit dodgy to me. From what I can tell, and I admit I'm not an expert, nor have I seen any of the actual papers yet, there's some confusion about what some of the terms being used actually mean. (Nothing new in that.)
Either it's a remarkable breakthrough, or it's an example of science being misinterpreted in an interesting way. Either way, there's a discussion that belongs more in New Science than in the Star Wars thread. |
|
| Back to top |
|
|
| Pietro_Mercurios Heuristically Challenged
Gender: Unknown |
| Posted: 30-09-2013 09:54 Post subject: |
|
|
|
| Anome_ wrote: | I think it's valid to discuss this in New Science. Especially as the whole thing seems a bit dodgy to me. From what I can tell, and I admit I'm not an expert, nor have I seen any of the actual papers yet, there's some confusion about what some of the terms being used actually mean. (Nothing new in that.)
Either it's a remarkable breakthrough, or it's an example of science being misinterpreted in an interesting way. Either way, there's a discussion that belongs more in New Science than in the Star Wars thread. |
I think it belongs in both. Although, I admit that I posted the story in the Star Wars thread partially to tease the fans.
Seriously, some of the use of language, i.e. 'coax photons into binding together to form molecules' reads as not much better than pseudo-scientific gibberish. I blame the journalist, though. |
|
| Back to top |
|
|
| Anome_ Faceless Man
Great Old One Joined: 23 May 2002 Total posts: 5377 Location: Left, and to the back. Age: 45 Gender: Male |
| Posted: 30-09-2013 10:29 Post subject: |
|
|
|
| Yeah, I think it's a confluence of wishful thinking on the part of the press, and a badly worded press release. |
|
| Back to top |
|
|
| ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
| Posted: 30-09-2013 12:57 Post subject: |
|
|
|
| I'd love a Light Sabre. I'd go to the Tory conference, smiting to the left and to the left. |
|
| Back to top |
|
|
| Mythopoeika Boring petty conservative
Joined: 18 Sep 2001 Total posts: 9109 Location: Not far from Bedford Gender: Unknown |
| Posted: 30-09-2013 19:24 Post subject: |
|
|
|
| ramonmercado wrote: | | I'd love a Light Sabre. I'd go to the Tory conference, smiting to the left and to the left. |
But...wouldn't that leave all the right-wingers? |
|
| Back to top |
|
|
| Analis Great Old One Joined: 12 Apr 2006 Total posts: 851 Gender: Unknown |
| Posted: 30-09-2013 20:53 Post subject: |
|
|
|
| Is this a possible explanation for UFO cases involving truncated beams (also called sometimes solid light) ? |
|
| Back to top |
|
|
| ramonmercado Psycho Punk
Joined: 19 Aug 2003 Total posts: 17933 Location: Dublin Gender: Male |
| Posted: 01-10-2013 02:03 Post subject: |
|
|
|
| Mythopoeika wrote: | | ramonmercado wrote: | | I'd love a Light Sabre. I'd go to the Tory conference, smiting to the left and to the left. |
But...wouldn't that leave all the right-wingers? |
No, I'd go in a circle. |
|
| Back to top |
|
|
| gncxx King-Size Canary
Great Old One Joined: 25 Aug 2001 Total posts: 13561 Location: Eh? Gender: Male |
| Posted: 01-10-2013 22:34 Post subject: |
|
|
|
| Analis wrote: | | Is this a possible explanation for UFO cases involving truncated beams (also called sometimes solid light) ? |
Solid light holograms could be interesting (yes, I did think of Red Dwarf). |
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
FAQ
Search
Memberlist
Usergroups
Profile
Log in to check your private messages
