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Comments: 143 +- Hardware: A "Photon Machine Gun" For Quantum Computers on Monday September 28, @12:23AM
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by
kdawson
on Monday September 28, @12:23AM
from the entangle-this dept.
from the entangle-this dept.
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An anonymous reader writes "Generating entangled photons in a reliable way is impossible right now, stalling the development of the optical quantum computers that would use entangled photons as quantum bits (qubits). Because entangled photons can only be produced at random — which takes time — the most powerful optical quantum computing device use only 6 qubits. UK and Israeli quantum physicists have designed a blueprint for a 'quantum machine gun' that fires out barrages of entangled photons on demand. They think within a few years this device will be built, and could lead to quantum computing using 20 to 30 qubits. Every additional qubit doubles the computing power, so these quantum computers could outperform any existing classical computer, the researchers say. The quantum machine gun is described as 'one of the most exciting theoretical proposals I've read in five years' by a leading quantum physicist." The research was published in Physical Review Letters earlier this month.
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Science: Caltech Scientists Film Photons With Electrons 46 comments
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For certain problems. (Score:5, Interesting)
Every additional qubit doubles the computing power, so these quantum computers could outperform any existing classical computer, the researchers say.
But only for probabilistic algorithms. It's not going to be faster at everything.
Re:For certain problems. (Score:5, Funny)
So Whpt if we occjsion?lly fl#p a fwe bits.
Parent
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It'll be like a Quantum Rambo. You'll take out a hell of a lot of Scenery with your spray
no peeking (Score:5, Funny)
It's going to be faster at everything.
Parent
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Re:no peeking (Score:4, Informative)
First, let's look at a fair attempt to explain why quantum indeterminacy is not just the same thing as classical indeterminacy (like your two particles, which by your question were presumably determinate in the classical model, at least until they became entangled). You seem to be reasoning much as the following note claims early quantum physicists tried to, when they first grappled with Heisenberg's uncertainty principle and the question of knowing the position and velocity of an electron simultaneously. I give you someone deliberately trying to put the concept in normal, natural language and not use any actual math:
http://www.uhh.hawaii.edu/~ronald/310/Quanta.htm [hawaii.edu]
One point is, the interpretation that we can't know both position and velocity at the same instant, therefore the electron doesn't have both at the same instant, doesn't explain that thing you refer to as "with no regard to distance". This is what sometimes gets called "Spooky action" and is related to non-locality in general. Starting from the interpretation that it's not our not knowing that causes the indeterminacy but the indeterminacy which causes our not knowing turns out to be putting the horse back in front of the cart. Once people started working from the idea that the indeterminacy is fundamental and not like your example of the balls (where there is a definite color for each, and the observer just doesn't know it yet), they started making progress on figuring out how entanglement could be faster than light.
http://www.absoluteastronomy.com/topics/Quantum_indeterminacy [absoluteastronomy.com]
This is about what non-locality really means: One consequence is that we can't assign a local cause (such as: a localized observer hasn't looked yet) to explain why something on the quantum level is determinate, or we lose the ability to explain how the faster than light part happens.
Just as the original QM problem was about determining position and velocity, talking about "non-localizable" (position), and instantanious/faster than light (velocity) is two ends of the same stick. The more you prove that the action happens much faster than the limitation of light-speed, the more you can't claim the action is caused by anything in a particular locale.
Parent
Re: (Score:3, Informative)
OK, you measure photon phase with a polarized lens. The way you measure the phase is to pass the photon through a polarized lens at an arbitrary angle. Unfortunately, all you can measure about the phase is whether the phase matches that of the lens - either the photon makes it through the lens, which means the photon had the phase of the lens, or it doesn't, which means the photon had a phase at 90 degrees to the lens. There's lots more to say about this, but I think this is enough to explain the answer
Re: (Score:3, Interesting)
The relevant theory here is Bell's Theorem [wikipedia.org] (or Bell's Inequality.) The principle of entanglement has been shown experimentally using some clever approaches based on probability.
If you measure a specific property of two entangled particles, you are correct in saying that there is no way we could know if the result of the measurement was predetermined. However, experiments were set up in which a large number of pairs of particles were measured. Each measurement recorded one of several possible properties, cho
Re: (Score:3, Funny)
It's going to be faster at everything.
It's going to be simultaneously faster and not faster at everything.
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Well yes and no
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Well... it is both.
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Of course, as of yet it isn't even known if a classical computer can calculate NP complete problems in polynomial time. P!=NP is still a conjecture.
BTW, the correct arXiv reference is arXiv:quant-ph/0601151 [arxiv.org]. After all, there's also astro-ph/0601151, cond-mat/0601151, hep-ph/0601151, hep-th/0601151, math/0601151 and physics/0601151, none of which are rele
Re: (Score:2)
Every additional qubit doubles the computing power, so these quantum computers could outperform any existing classical computer, the researchers say.
As all the photons are entangled with the same electron it simply means that 1 qubit is going to be easier to read because it is being represented by multiple photons and an electron the idea that the more photons you entangle the more qubits you get is nonsence because they are all essentially linked so any change on one will be mirrored on the others
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They're not absent, you just don't know them.
How about the first known ships? African. Irrigation? African. Early mathematics? Early medicine? African.
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Calling the Egyptians 'African' is a kind of stretching.
Well, they lived mostly in geographical Africa, but the rest of Africa didn't really adopt their culture/inventions.
Europe, on the other hand did.
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"Calling the Egyptians 'African' is a kind of stretching"
Bullshit.
If what are you talking about black people, then say "black people". If you want to use the word "African" then Egyptians are included by necessity.
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If what are you talking about black people, then say "black people". If you want to use the word "African" then Egyptians are included by necessity.
Tell that to those who call themselves African American.
Re: (Score:2, Interesting)
"Note that Japan is a barren rock without any natural resources. "
It has a huge amount of sea, same as Ancient Athens, same as the Roman Empire, same as Phoenicia and Venice and Great Britain and America, but unlike most of the African nations. (Egypt had its river).
History tells us that it's the sea-abundant civilizations that created the greatest amounts of culture -- contrast Athens to Sparta, Venice to Prussia, America to the Soviet Union -- and yeah Japan to Africa.
One of the reasons is because the sea
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Also, the Japanese have done quite well. They invented the blue light-emitting diode, hybrid engines for cars, process technologies for cost effectively producing large LCD screens, etc.
You forgot tentacle pr0n and bukkake.
Qubit does not double power in traditional sense? (Score:4, Insightful)
Every additional qubit doubles the computing power, so these quantum computers could outperform any existing classical computer, the researchers say.
I thought that the "power doubling" was not in a traditional sense.. the qubit is fantastic at pattern matching and search functions, but no better than a classical computer for something like, say, a video game requiring finite mathematical calculations. I'd state this as a fact, because I've read this in at least a couple places, but seeing as how quantum physicists haunt this forum, I can't say I know as well as them. But this power is only useful in very specific circumstances, AFAIK.
Re: (Score:3, Interesting)
I thought that the "power doubling" was not in a traditional sense.. the qubit is fantastic at pattern matching and search functions
Which is all that really matters for breaking encryption, and is the whole reason we have computers in the first place.
So my question is how many bits of encryption do I need to keep a 20~30 qbit computer out of my truecrypt partition?
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If you are very unfortunate, n qubits can map 2^n -1 bits. -1 because 2^0 = 1, and that'd just be weird.
If this is the case, then a 6 qubit machine maps 63 bits, but 20 would map 1,048,575 bits (1 Mbit of information) and 30 would map 1 Gbit of information.
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Uh, how many states can no bits exist in? I would've said 1, myself.
Return type void is always the same.
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Re:Qubit does not double power in traditional sens (Score:2)
On the other hand, some problems like collision testing are really just pattern matching or search functions, and that has a huge amount of applicability to game design. There are many other similar problems that, at first blush, sound easy, but turn out to be quite difficult, and I've yet to see a modern game with physics that doesn't somehow manage to get objects stuck in floors or falling through levels.
Not particularly useful against an insurgency (Score:4, Funny)
Israeli quantum physicists have designed a blueprint for a 'quantum machine gun'
In other news, Palestinian quantum physicists have designed shoulder-mounted quantum launchers and quantum vests in response.
Civilians are hopeful for peace and terrified for escalation of hostilities.
Re: (Score:2, Interesting)
It's a sad world we live in, that in the presence of scientific breakthroughs and ingenuity, one of the first thoughts that arises is of the fighting that surrounds that part of the world. I suppose Yom Kippur is a surprisingly appropriate time for reflection on that though.
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Re:Not particularly useful against an insurgency (Score:5, Informative)
Harmful harmful force? Dude i think you need to re-evaluate your worldview if you want to blame the group being constantly attacked and threatened with the explicit goal of genocide for everything wrong. The mere presence of jews in the middle east produces the reaction you see from Hamas and friends, whether or not Israel was officially a state would have fuck all to do with anything other than the success of those attempts at genocide.
Hell Hamas' own govt charter explicitly blames the jews (merchants of death) for everything from the french and russian revolutions to both world wars while outright demanding the death of every jew and anyone who refuses to participate in said genocide.
Parent
Re: (Score:2, Insightful)
Re:Not particularly useful against an insurgency (Score:5, Insightful)
So in other words you want them to do the exact opposite of the only thing keeping the number of rockets and mortars fired at Israeli (arab AND jew) civilian targets in the low to mid thousands rather than much higher.
What did we do with vietcong tunnels in vietnam? The ones used for moving and storing weapons and occasionally fired from. We demolished them. What does israel do with houses build on top of tunnels or used as weapons caches. They demolish them. If people don't want their house bulldozed all they need to do is say "No you cannot indiscriminately attack civilians from my house or store/transport the weapons you use to do that in/through my house."
As for the borders, wtf do you suggest they do? Just open them up for MORE weapons to get smuggled through?
The religious extremists in the region already HAVE a concrete and unarguable reason for doing what they do, it's called genocide. This has NOTHING to do with Israel as a state and everything to do with the fact that there are jews and christians (but mostly jews) over there that aren't dead yet. Read the Hamas charter sometime, the slaughter of all jews everywhere is listed as mandatory for the messiah to come in it. If you think anything Israel does has ANY bearing on anything the palestinians do you're delusional.
There's a palestinian couple living a few apartments away from me, do you know what he calls palestinians that don't want to kill all the jews? Israelis. Just like the million and a half arabs living in israel that are ALSO a target of palestinian violence because they don't join the genocidal crusade Hamas is currently leading.
Parent
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They ARE the previous land owners despite other people constantly trying to wipe them off the face of the earth with varying degrees of success. You REALLY don't know your world history do you... let me help you, what was the region called before the romans renamed it after the philistines after (suprise suprise) forcing the jews out. Or for a more recent example who was it that got all the "palestinians" to move to where they are today so that which nations' militaries would have a clear path to push the j
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http://lmgtfy.com/?q=hamas+charter [lmgtfy.com]
Klingons! (Score:2)
Again, Trek predicts the future.
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ObCompJoke... (Score:4, Funny)
imagine a Beowulf cluster of... NO! NONONO!
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Explain the hype, please? (Score:2, Interesting)
Ok, so on this site bursting with intelligent, educated folk, the following question(s) might make me look like a village idiot, but what the hell. It's damn interesting stuff and I want to know!
Exactly how does quantum computing work? I have a fleeting grip the basic stuff; qubits existing with states 0, 1 and "superposition" (i.e. all possible states) and that by actively measuring it's state (sending a photon or whatever bumping into it) you collapse it, and it's entangled mate, into a "classical state".
Re:Explain the hype, please? (Score:5, Funny)
Ok, so on this site bursting with intelligent, educated folk...
You lost me at "Ok".
Parent
Re:Explain the hype, please? (Score:4, Informative)
Ok, I just wrote a lengthy reply, and then by accident hit "refresh", and all the text was gone :-(
Therefore here the short version:
Parent
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storing the state of 30 qubits needs about 16 GB, which is large, but perfectly doable in todays computers
I can haz ur USB for teh ReddyBoozt?
kthxbai.
Re: (Score:3, Informative)
Ok, I just wrote a lengthy reply, and then by accident hit "refresh", and all the text was gone :-(
You're welcome. [mozilla.org]
Re: (Score:3, Informative)
Bad analogy time.
The simplest way to factor a large number is to just try to divide it by 2, by 3, etc. Once you've divided it, you now have 2 smaller numbers to factor. Repeat until you get a prime. This takes a long time for a large number because you have to try it over and over again.
With a quantum computer you can do all of these computations in parallel, and then arrange for all of the non-factors to cancel each other out, meaning that you can only measure a legitimate factoring. (Getting all of th
How Shor's algorithm works (the problem with QC) (Score:3, Interesting)
In fact, I first studied Shor's algorithm in order to understand why good programmers weren't looking at it, generalizing it, and writing a million more algorithms. I was disappointed to learn that we are not far enough along to describe a universal quantum c
Duh..... (Score:2)
It's called a "Strobe Light", stupid.
I know.....bad joke.....
Dirty Erwin (Score:5, Funny)
I know what you're thinking: "Did he flip six qbits or only five?" Well, to tell you the truth, in all this excitement I kind of lost track myself. But being as this is a Photon Machine Gun, the most powerful quantum entanglement source in the world, and would blow your head clean off, you've got to ask yourself one question: Is the cat dead or alive ? Well, is it, punk ?
Heh (Score:5, Funny)
The quantum machine gun is described as 'one of the most exciting theoretical proposals I've read in five years' by a leading quantum physicist.
The long winter nights must just fly by.
Re: (Score:2)
involving high speed protons,
Bt wot abt deez hispeed *photons*?
Do they go *whoosh*?