Quantum computer works best switched off

dr. what · Post by **dr. what** » 2006-02-22 10:12pm

Even for the crazy world of quantum mechanics, this one is twisted. A quantum computer program has produced an answer without actually running.

The idea behind the feat, first proposed in 1998, is to put a quantum computer into a “superposition”, a state in which it is both running and not running. It is as if you asked Schrödinger's cat to hit "Run".

With the right set-up, the theory suggested, the computer would sometimes get an answer out of the computer even though the program did not run. And now researchers from the University of Illinois at Urbana-Champaign have improved on the original design and built a non-running quantum computer that really works.

They send a photon into a system of mirrors and other optical devices, which included a set of components that run a simple database search by changing the properties of the photon.

The new design includes a quantum trick called the Zeno effect. Repeated measurements stop the photon from entering the actual program, but allow its quantum nature to flirt with the program's components - so it can become gradually altered even though it never actually passes through.

"It is very bizarre that you know your computer has not run but you also know what the answer is," says team member Onur Hosten.

This scheme could have an advantage over straightforward quantum computing. "A non-running computer produces fewer errors," says Hosten. That sentiment should have technophobes nodding enthusiastically.

Journal reference: Nature (vol 439, p 949)

From issue 2540 of New Scientist magazine, 22 February 2006, page 21

bilateralrope · Post by **bilateralrope** » 2006-02-22 10:19pm

This scheme could have an advantage over straightforward quantum computing. "A non-running computer produces fewer errors," says Hosten. That sentiment should have technophobes nodding enthusiastically.

Fewer ? So it can produce errors when not running ?

At this stage I'm thinking it may be best for me to pay no attention to quantum computing untill it looks like I may get to use one soon.

AK_Jedi · Post by **AK_Jedi** » 2006-02-22 10:58pm

Stuff like this can get really confusing really fast. Its best not to try to use your intuition on problems like these.

Post by **Mr Bean** » 2006-02-22 11:04pm

Wonder what that smell is? That's the stench of your brain quietly melting and running out your ears.

In short and in english, Quantum computers are so complicated and on such a vast yet small scale, quantum mechanics comes directly into play(Hence the name.) and in the Quantum world, up is down, blue is green and black is white. At least it is now this instance, five minutes from now(Or three picoseconds ago) up might have been Tuesday and blue might be white and black was a small toll both in the vicnity of New Jersey.

Hawkwings · Post by **Hawkwings** » 2006-02-22 11:34pm

so eventually, we won't build banks of quantum computers to ponder the mysteries of the universe... but get the answers anyways because we *almost* built them?

SyntaxVorlon · Post by **SyntaxVorlon** » 2006-02-22 11:56pm

Wow, that's scary. Next the computers will be making output for programs that haven't been written.

Sonnenburg · Post by **Sonnenburg** » 2006-02-23 12:13am

Mr Bean wrote:In short and in english, Quantum computers are so complicated and on such a vast yet small scale, quantum mechanics comes directly into play(Hence the name.) and in the Quantum world, up is down, blue is green and black is white.

So, quantum computers are a never ending collection of "in Soviet Russia" jokes, is that it?

Not to mention the fact that you'd think if the computer gives answers without running, it's time to call in an old priest and a young priest.

But seriously, this just raises so many weird questions. Like, if the computer's giving answers and it's not running, how are you going to turn it off? And who cares how good the program you wrote is if it isn't actually being run? And how do we know a non-running program produces fewer errors; if we're not running the program, how do we know it's right? And what in God's name will happen when there are errors, will it start running? Do you call tech support to complain that your quantum computers running and you want to make the thing stop running so you can do something with it? "This program has performed an illegal operation and is starting up."

SyntaxVorlon · Post by **SyntaxVorlon** » 2006-02-23 12:19am

"In Soviet Russia, the Cat is Dead or Alive."

No it just doesn't work.

But seriously, this just raises so many weird questions. Like, if the computer's giving answers and it's not running, how are you going to turn it off? And who cares how good the program you wrote is if it isn't actually being run? And how do we know a non-running program produces fewer errors; if we're not running the program, how do we know it's right?

According to the OP, they still have to have something going through the program, its just that the computer isn't actually using any processing power. Just wait 20 years and they'll have cellphone sized game consoles rendering Return of the Sith level graphics in real time, using two double AA batteries.

Civil War Man · Post by **Civil War Man** » 2006-02-23 12:20am

Mr Bean wrote:In short and in english, Quantum computers are so complicated and on such a vast yet small scale, quantum mechanics comes directly into play(Hence the name.) and in the Quantum world, up is down, blue is green and black is white. At least it is now this instance, five minutes from now(Or three picoseconds ago) up might have been Tuesday and blue might be white and black was a small toll both in the vicnity of New Jersey.

Which is why the Quantum sorting algorithm is so fun.

Quantum Sort: Look at the sequence, then destroy all universes where it is not in order.

CaptainChewbacca · Post by **CaptainChewbacca** » 2006-02-23 12:28am

So, when do we plug it into the Heart of Gold?

wolveraptor · Post by **wolveraptor** » 2006-02-23 12:36am

Sonuvabitch, I'm not even going to try to understand this shit any more. Quantum natures flirting can produce an effect? What the fuck?

On the upside, this seems like another reason to respect U of I as an institution. I'm actually planning on going there. I used to live in the area, so I'm familiar with it, and even now, I'm only about 45 minutes away. And it appears to be pretty damn prestigious.

Lord Zentei · Post by **Lord Zentei** » 2006-02-23 02:11am

The only good quantum computer is a non-running quantum computer.

Sonuvabitch, I'm not even going to try to understand this shit any more. Quantum natures flirting can produce an effect? What the fuck?

Let go your sanity, mwa ha ha haa!

Seriously, though: I am unfamiliar with the Zeno effect, but on the quantum level, things can interact even though the particles don't come into actual contact.

Faram · Post by **Faram** » 2006-02-23 02:14am

I want one of those.

Bring out your encryption, I will hack you with it

darthdavid · Post by **darthdavid** » 2006-02-23 02:32am

*Tilts head to side*
Mrrrrrr?

bilateralrope · Post by **bilateralrope** » 2006-02-23 03:35am

Faram wrote:I want one of those.

Bring out your encryption, I will hack you with it

Only if you dont have the decryption program running

Faram · Post by **Faram** » 2006-02-23 04:12am

bilateralrope wrote:
Faram wrote:I want one of those.

Bring out your encryption, I will hack you with it
Only if you dont have the decryption program running

Well I cant program, so I can do anything with it!

My next trik after cracking and hacking will be squaring the circle.

Brother-Captain Gaius · Post by **Brother-Captain Gaius** » 2006-02-23 04:21am

Cool. So Limbo does exist. Wonder if we'll run into any Gith?

Molyneux · Post by **Molyneux** » 2006-02-23 08:47am

Gentlemen...we hold in our hands the key to improbability generation.

Now to see about getting invited to 'those' sorts of parties, and collect some underwear...

dragon · Post by **dragon** » 2006-02-23 09:01am

Man even though I have taken a couple classes in quantum physics this stills boggles the mind.

LaCroix · Post by **LaCroix** » 2006-02-23 09:20am

*Replaces some burnt-out neurons in his Brain-raid*

YEAH!

They finally have a computer that can work with my style of programming!

Rye · Post by **Rye** » 2006-02-23 12:27pm

This is one of the most mad things I have ever read. I wonder how stackable such a phenomenon is, like could you stack several interlocked programs that don't really run? How large could it go? What would happen if you built a looping system around this? Would it never run but be constantly running?

CaptainChewbacca · Post by **CaptainChewbacca** » 2006-02-23 01:27pm

I am what you would call an "ammateur theoretical physicist", being that I do the concepts and not the math. The best way to go is to just accept it and try not to dig to deep or you WILL hemmorage your brain.

Lord of the Abyss · Post by **Lord of the Abyss** » 2006-02-23 01:43pm

Reminds me of a quantum mechanical method of scanning an object I read about in Scientific American years ago, where the potential for interaction let it analyze it's target, without any actual interaction. So now we can have a scanner that does nothing, connected to a computer that's not on, and get a result !

Oh, and don't ask me how the thing worked; I think I vaguely got the idea for about ten minutes after I read the article. After that, it apparently fried the brain cells involved.

Bounty · Post by **Bounty** » 2006-02-23 02:02pm

in the Quantum world, up is down, blue is green and black is white. At least it is now this instance, five minutes from now(Or three picoseconds ago) up might have been Tuesday and blue might be white and black was a small toll both in the vicnity of New Jersey.

Troubleshooting would be a bitch.

CaptainChewbacca · Post by **CaptainChewbacca** » 2006-02-23 02:02pm

I wonder if NOT thinking about a quantum computer can fry your brain.