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Scientists Build New Type of Photon Gun
KentuckyFC writes "Single photons are surprisingly difficult to generate. But since they are crucial for quantum communication, a number of research groups are working on photon guns that fire single photons on demand. The problem they have come up against is that making the photons identical is proving harder than expected. Now a group in Cambridge, UK, has cracked the problem using a quantum dot on a transistor to emit single photons that are essentially identical. In the process, the group has developed an entirely new technique to trigger photon emission (abstract on the physics arxiv)."
Is it possible to correctly attach this photon gun to a shark's head?
I am officially gone from
great, bloody typical. another /. story to make me feel stupid. FTFA:
/. reader could supply us all with an explanation why this is a big deal then on behalf of the others I'll be thanking you in advance.....
"We generate indistinguishable photons from a semiconductor diode containing a InAs/GaAs quantum dot. Using an all-electrical technique to populate and control a single-photon emitting state we filter-out dephasing by Stark-shifting the emission energy on timescales below the dephasing time of the state. Mixing consecutive photons on a beam-splitter we observe two-photon interference with a visibility of 64%"
snooze. snooze. snort. no mention of stun, kill, slicing, death ray, x-ray specs or photonic propulsion, so there is nothing there for me.
if some obliging, and more informed
IIRC, individual photons are actually visible to darkness-adapted eyes...
What I'm listening to now on Pandora...
And nobody yet has made a witty remark about photon torpedoes being next?
There is no "I disagree" mod for a reason. Flamebait, Troll, and Overrated are not substitutes.
No folly is more costly than the folly of intolerant idealism. - Winston Churchill
OMGPHOTONS!!!
?
pirated?
Arr! give me all your photons!
Sure, placement and receipt are a huge factor, but this is still a huge step forward.
Also (much more difficult to control) what the "phase" of it is. Lasers achieve tremendous frequency-uniformity, which is quite nice, but the amazing thing is that their photons are essentially mostly phase-locked, so each is identical to the last. It means that one can get tremendous power a large distance with them. But lasers are inherently producers of large populations of photons (in a sense, you need a lot of photons to control the mechanisms which produce more photons) at the same time. The ability to produce single photons of a given frequency and random phase is relatively easy; producing single frequencies and single phases is much more difficult.
I think that's the April Fools joke -- there are no April Fools joke stories.
Though, I want my ZOMG!!! PONIES!!!! theme back for one day.
General Relativity: Space-time tells matter where to go; Matter tells space-time what shape to be.
Naw, that's more like a photon sprinkler.
Well, imagine if it were shooting out REALLY REALLY BIG photons one at a time. Wouldn't that be a photon torpedo?
"Aye, Cap'n. It was inwented in Russia."
mcgrew's razor: Never attribute to stupidity that which can be explained by greedy self-interest
ob [need citation] but still... I though that the eye wouldn't trigger on fewer than 8 photons in 1/25 seconds
I will not give in to the terrorists. I will not become fearful.
So far today no joke stories.
Apparently they were all voted down.
mcgrew's razor: Never attribute to stupidity that which can be explained by greedy self-interest
Jeez! That DRM gets everywhere!
Gentoo Linux - another day, another USE flag.
Um, Wal Mart has a good selection of ammo...
I don't recall seeing any photons there though..
You just got troll'd!
The figure I had quoted to me was that you have a 50% chance of seeing a single photon in an otherwise completely dark room, unfortunately the guy who said it was a grad student and can't be cited. Here's a link, though. http://www.accessexcellence.org/AE/AEC/CC/vision_background.html paragraph ten.
Single photons are a lot like single women in Utah. Most of them are essentially the same and inherently unstable.
Because of the Heisenberg Uncertainty relations between photon number and phase, being able to produce exactly one photon (which is what they do in this case) means that the photons have and undefined phase. However, this is not important for the applications that they use. If you were to send such a photon into an interferometer, you would still see interference as the photon interferes with itself and a relative phase can develop between the two modes/arms of the interferometer. Almost all classical interference is just single photon interference scaled up. Here the challenge is to ensure that each of the successive photons emitted are indistinguishable. The photons must have the same wavelength, there wavefunctions the same shape, and there emission time must be short enough to make sure that dephasing mechanisms within the quantum dot do not affect when the photons are emitted (low jitter). With an ideal source of indistinguishable photons (which is very different from a laser source), it is possible to combine the photons and obtain higher order quantum interference effects where two different photons interfere with one another as opposed to just themselves. This effect can be used to create simple logic gates used in quantum computing.
So, is there a shark-mounted application for this or are these guys just wasting time?