Quantum Computer Works Better Shut Off 376
waimate writes "A New Scientist article relates how its possible to get answers from a quantum computer even when your program isn't running." From the article: "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."
Gee whiz (Score:4, Funny)
Re:Gee whiz (Score:3, Funny)
I'll admidt I really don't understand what the article is talking about, but I'm pretty sure it has something to do with Heisenberg's Uncertainty...
Re:Gee whiz (Score:2)
Or something.
However, first thing I did was check that it wasn't dated 1st April...
Re:Gee whiz (Score:5, Funny)
This sounds like zen buddhist computer science. Either that or something cooked up after a little too much of the green stuff. Still, makes me wonder. What kind of software do you run... erm, not run... on a computer that isn't running? Non-existent programs, like Duke Nukem Forever?
Hrm. That would open up a whole new industry. That'd be a fun profession, full-time vaporware programmer... hell, I'm gonna start right now. I'm officially announcing VaporWorks, an integrated word processor, spreadsheet, calendar and presentation software suite, not running on your computer in the near future. If anyone needs me, I'll be on the beach in Cancun spending my startup money, not busy working 16 hour days to get it ready.
Re:Gee whiz (Score:3, Funny)
After all, it's always best to try to make your product do everything, even if it sounds impossible. Apparently VC investors like that.
Schrodinger's programmer (Score:5, Funny)
No, here's what you do. You build a shielded, sound proofed room with your computer workstation, a nice entertainment center, bar and comfy recliner. Then you seal yourself in the room so no one can tell what you're doing. Either you have the computer turned on and are hard at work programming or you're kicked back doing nothing enjoying yourself. Call it Schrodinger's programmer.
Now, if your computer is hooked up to the Zeno effect device described in the article, it should be able to read the results of your work whether you actually did it or not. This should usher in a revolution in work environment for programmers everywhere.
Re:Gee whiz (Score:4, Funny)
Dammit Bill (was Re:Gee whiz) (Score:5, Funny)
Re:Gee whiz (Score:3, Informative)
No, you can't run non-existent programs (i.e. those who have 0% chance of existing.) However, the quantum computer would be able to run a program that has a non-zero waveform. I'm assuming this computer would be similar to Discworld's Hex [wikipedia.org].
Re:Gee whiz (Score:3, Funny)
What it means is that ... (Score:2)
New Underpants business model for success (Score:5, Funny)
1. Buy super quantum computer
2. ???
3. Profit!
We now know step 2. Shut the computer off and go for a long weekend.
Re:Gee whiz (Score:5, Insightful)
Neither did whoever wrote the article.
It works like this:
1) Define some classical terms, like "running" and "actually"
2) Apply them incorrectly to quantum situations
3) ob. ????
4) Profit!
The components of the photon wavefunction that are "not actually running the program" become entangled with the components of the photon wavefunction that "are actully running the program", and therefore they carry information regarding the state of those components.
If we think about this in classical terms, where we incorrectly and falsely imagine that each component of the wavefunction represents a classical trajectory through the apparatus, we could incorrectly and falsely say that photons that have not followed classical trajectories through the part of the apparatus that does the quantum computation have not run the program.
But the clear contradiction of that statement makes the slippery bullshit marketing-speak of the article clear: of course a photon that has followed any classical trajectory whatsoever has not run the quantum program. And to claim that "a photon whose wavefunction is entangled with the program has not run the program" too obviously has the same epistemological and moral status as giving away "free" products that only require a "small" processing fee to claim.
One is motivated to ask, "Why doesn't entanglement with the program state count as 'really' running the program? What is this 'real' thing you keep talking about?" Admittedly, entangling things in this way is a different way of running the program, and is really rather clever, but to promote the results in this way is just attention-grabbing marketing, unworthy of the name of science.
This kind of abuse of language is similar to that of the "quantum teleportation" folks, whose deliberately misleading claims often make it sound like something other than the ontologically-problematic quantum state is being "teleported."
Re:Gee whiz (Score:3, Insightful)
Second: you clearly don't understand the experiment, so why accuse the authors of 'bullshit marketing-speak'? 'On and Off' are not necesarily classical notions; the method to implement on and off is quite simple -- you just use a beamsplitter.
You also seem to have the impression that just because two photons are entan
It just sleeps on it. (Score:4, Funny)
Re:It just sleeps on it. (Score:2)
I also relies on the quantum properties of brain matter.
Here is how it works:
Step 1. You take your text book and open it to the middle of the section you need to know for tomorrow.
Step 2. Insert a bookmark into this spot (not a scrap of paper, a bookmark) and close the book around it.
Step 3. Place the book + bookmark under your pillow.
Step 4. Sleep on it.
Step 5. When you rise (fully
Better when shut off! (Score:3, Funny)
I know my computer... (Score:2)
Oh What Fun (Score:2, Funny)
Of course it produces less errors! (Score:2)
Duh! It's not running so it can't produce errors!
Works better when shut off? (Score:2)
Seriously though, this statement made my day: "A non-running computer produces fewer errors," says Hosten.
How do I convince my boss that I can work this way, too?
Gee, That's Useful(less?) (Score:2)
Hang on.. (Score:2, Funny)
How can it work better when its off than when its on. Its either on or off, it can't be on and off at the same time!
</sarcasm>
That's easy! (Score:3, Funny)
How can it work better when its off than when its on. Its either on or off, it can't be on and off at the same time!
Schroedinger + Heisenberg == Schroedenberg's Uncertain Cat Principle
Deep Thought... (Score:2)
All we need to do now is program the question...
Z.
Re:Deep Thought... (Score:5, Funny)
All we need to do now is program the question...
Duh. The question was: "An African, or a European Swallow?".
Think about THAT for a second.
You mean like us? (Score:3, Interesting)
I've read several times how not thinking about a problem will lend itself to a solution.
ie Go take a walk, get a cup of coffee, take a nap.
Interesting, or maybe I just need coffee.
Re:You mean like us? (Score:3, Informative)
There's a neat book by a guy named Michael Talbot called The Holographic Universe [amazon.com] that talks about this idea quite a bit. He often cites David Bohm, and if you want to get into Bohm's thoughts on the potentially holographic nature of the universe and how that relates to us through quantum effects, you should read Bohm's Wholeness and the Implicate Order [amazon.com]. Bohm is/has been a leading researcher in the field of Quantum Physics.
In short form: Talbot's assertion is that some part of our brain operates like a
Oh Great: Ultimate in quantum malware (Score:3, Funny)
For all we know this malware is already running.
Re:Oh Great: Ultimate in quantum malware (Score:5, Funny)
"You imbecile! You let that virus infect our systems!"
"But I didn't open the file!"
"Yes, but there was a 2 percent chance that you would have, so two percent of our data was affected... and included in that two percent was your entry in the payroll database. So I'm not firing you, but you won't be paid anymore."
"This sucks! I'm going to commit Schroedinger's Seppuku! You'll regret this when I walk in that door with my guts both spilling out and in my body!"
Re:Oh Great: Ultimate in quantum malware (Score:2)
Re:Oh Great: Ultimate in quantum malware (Score:3, Funny)
Funniest sentence from the article:
Ha! Or from the point of view of the toxoplasmosis spores that live in the cat's brain...and... (Score:5, Funny)
Schrödinger's PC (Score:2, Funny)
Misleading (Score:5, Informative)
Does anyone know what is new here ?
Re:Misleading (Score:4, Insightful)
The actual journal article that New Scientist is referring to was just published: Nature 439 949 [nature.com]. I'm not sure if that link will work if you're not at an institution that has a subscription, but you'll probably at least get to see an abstract.
A few bits of background: New Scientist's coverage of quantum information is sometimes horrible. Therefore, it's not surprising that the New Scientist article makes no sense but contains lots of exciting fluff. That said, these guys do have something interesting.
I skimmed through the Nature article, and it looks interesting. It's especially nice that they have an experimental implementation. Nonetheless, the bit about the quantum computer being "off" is just silly.
Here's a summary of how it works, stripped of some hyperbole and converted into something more like plain english (note: qubit means quantum bit).
(1) Create a "control qubit" and some output qubits, with the control qubit initially set to 0, which we will take to mean off.
(2) "Rotate" the control qubit into a superposition of 1 (on) and 0 (off), with most of the "amplitude" being for the 0 state (the qubit is mostly off)
(3) Apply whatever algorithm to the data and the output qubits, conditional on the control bit being on. (Note: we don't actually measure anything here--this is entirely a unitary operation).
(4) Perform a weak measurement on the output qubits, which has the effect of reducing the amplitude of the output qubits being in something other than their initial state (which can only happen if the control qubit was on and the algorithm was applied), since the amplitude for that was small to begin with.
(5) Repeat (2) - (4) N times, such that, if the output bits are unmodified after each algorithm application, you end up with the control qubit in the 1 (on) state. Otherwise, you get the 0 (off) state.
(6) Profit!
This is the simple version, in which you only get to learn whether the application of the algorithm to the data gives you the default output or not. There's a more sophisticated version in which you learn more about the data.
There are a few catches here. One is that N has to be reasonably large, or the probability of an "error" in step 4 becomes an issue (by error, I mean that the weak measurement gives us the wrong outcome). Specifically, the probability of an error is 1 - cos^2N (pi / 2N), which scales as O(N^(1-4N)). Fortunately, that is exponential suppression of error, which is pretty good scaling. Another catch is that their particular experimental implementation used a non-scalable encoding. This isn't a major issue, but it means we should wait for an experiment using a scalable encoding before we really break out the champagne.
Re:Misleading (Score:3, Interesting)
There. Fixed it for ya.
Ever since Scientific American went pop-sci in the mid-90's, we've been without a decent, objective layman's science magazine that avoids sensationalising.
Science News weekly is probably the best, but it's written for a 10th grade audience.
Laziness... (Score:5, Funny)
In related news.... (Score:3, Funny)
Re:In related news.... (Score:2)
Re:In related news.... (Score:2)
Re:In related news.... (Score:2, Funny)
http://www.pcmag.com/slideshow_viewer/0,1205,l=&s
Re:In related news.... (Score:2)
It's more secure anyway.
Re:In related news.... (Score:4, Funny)
Funny, most users report the same thing.
Black Magic (Score:2)
When does stuff like this make people start to lose credibility? Are we there yet? IANAQM, but on a simple gut level I can't buy any of this.
Re:Black Magic (Score:5, Informative)
Just wait! (Score:2)
not according to v3, which may have just called (Score:2)
great... (Score:2)
sounds like another answer to a question no one asked.
42 (Score:2)
Re:42 (Score:2)
Running or not? (Score:2, Insightful)
Hieronymous machine? (Score:2)
Naturally, no one has ever been able to reproduce Campbell's results. Campbell was a great science fiction editor, but a real crank when it came to crackpot psuedoscience.
The Next Step (Score:4, Funny)
And the followup:
"Quantum Software Works Better Before Writing the Code Than After Writing the Code".
Re:The Next Step (Score:2)
So Quantum == Microsoft?
Re:The Next Step (Score:2)
Actually, that's what Microsoft software does. Remember how great WinXP was before anybody seen it?
How do you tell if it's running? (Score:2)
Good for cats (Score:2)
Bloody Stupid Johnson (Score:2)
Three and a bit. You gotta have it.
Just like my quantum clock! (Score:2)
Black Mesa? (Score:2)
The last of the voice logs from the test chamber read:
"Shutting down. No. Attempted shutdown! It's not... it's not... it's not shutting down!"
Wanna bet why?
Damn Quantum Scientists (Score:2)
Depends on what you consider "off" (Score:2)
Seems stupid to suggest it's "shut off" because it's not. I would consider "shut off" would mean it has no power flowing to it.
Did I time warp? (Score:2)
Re:Did I time warp? (Score:2)
Bahhhh (Score:2)
Thinking for you (Score:2)
Even a stopped clock is right twice a day (Score:2)
My computer does it too (Score:2)
Illusion (Score:2)
Could someone please explain this? (Score:3, Interesting)
Coming back here, the discussion consists entirely of moronic comments about Windows. Would someone with a clue care to provide some useful commentary?
Re:Could someone please explain this? (Score:3, Insightful)
Re:Could someone please explain this? (Score:3, Interesting)
1) In the Elitzur-Vaidman thought experiment, which part corresponds to the on-off switch?
2) Is the "non-running" experiment physically performed differently from the normal method, or is it a refinement made in the data?
Re:Could someone please explain this? (Score:3, Interesting)
>which part corresponds to the on-off switch?
The entire computer takes the place of the bomb(s). The "on-off switch" is really whether or not a photon enters the computer (thus running the program).
>2) Is the "non-running" experiment physically
>performed differently from the normal method,
>or is it a refinement made in the data?
The "experiment" only works when it is running. What's "non-running" is the computer, or perhaps more precisely, the co
Security risk? (Score:2)
I'm not talking about "quantum cry
Before it was switched on.. (Score:2, Funny)
Sweet! (Score:2)
Slashdot readers stumped (Score:2)
Re:Slashdot readers stumped (Score:2)
Hitch-hiker's Guide... (Score:2)
Re:Hitch-hiker's Guide... (Score:2)
The universe has a bug... (Score:2)
A story about magic (Score:2)
I don't have a clue. (Score:2)
Got d***n it. I've read the article (yes I did), I also had in introductory quantum phycics course in undergrad, but I still do not understand "how this is supposed to work".
Yes they say that using the Schrödinger's idea, they send a photon into the computer while inhibiting it by using a series of mirrors. This rises the photon into a "superposition
And curiously the answer is always... (Score:2, Funny)
Nature (Score:3, Informative)
http://www.nature.com/news/2006/060220/full/06022
http://www.nature.com/nature/journal/v439/n7079/a
This is an old result (Score:5, Interesting)
But this doesn't buy you anything. Quantum computers are reversible meaning they use no energy. And the computer has to spend just as long "doing nothing" as it would have spent doing the computation. And your computer is still tied up "doing nothing". So it's basically useless.
IANAP, but I'll try to explain... (Score:5, Informative)
Someone else already posted an useful background URL with is a good place to start:
http://en.wikipedia.org/wiki/Elitzur-Vaidman_bomb
Basically, what you have here is something called "interaction-free measurement". Because of the quantum mechanics work, a particle's wavefunction evolves in a certain way over time, which then "collapses" when you measure it to something specific. How it evolves is not deterministic, but probabillistic. Because of this, you can set up a quantum system whereby when you place a certain object in it at a certain place, you can change the whole system given the nature of what you add to it.
In this case, you have a quantum computer composed of mirrors that runs on photons. The mirrors are pre-set in a certain configuration to run a certain "program". No electricity is needed to "run" the program; you just inject photons into it and it spits out results when you measure it.
What they've done here is then place that computer in a certain location in an existing quantum mechanical system, the one which the photon comes from. This photon is associated with its own set of mirrors and detectors, and because of where and how the computer is placed into it, it effects the larger system.
Thanks to QM, you can then tweak the exterior system so that the chances of a photon ever actually getting to the quantum computer are infinitessimally small. But because there's still a small chance, the very nature of the computer in that location allows you to determine the results it would generate, even though a photon never actually gets into it to "run" it.
So, it's not to misleading to say the program never actually "runs". And you could say the computer isn't "on", but since it's just a mechanical-optical construct it's always "on". More importantly, though, is that exactly where the "computer" is becomes blurred; while it's true that it's particular programming is self-contained, by hooking it up to the external quantum system, you're sort-of making it a part of the computer as well. The "work" is being done by the photons outside the computer; remove them and you don't get anything.
Wow, reading the above, I didn't really do a good job of explaining this at all. But basically, even though the quantum program never actually executes, you still need to create it, and you still need to put it in a certain spot so that its quantum effect on the world around it can still be measured, and from that, you can infer what the program would actually do.
Bruce
Horrible mangled article. Better one: (Score:3, Informative)
Anticipated by BeOS (Score:3, Funny)
Obligatory MS Bashing... (Score:3, Funny)
Re:Answers.. (Score:2)
Re:Answers.. (Score:2)
And I want to go study this at university? If you need me, I'll be under the nearest bar.
Re:So how do we... (Score:5, Funny)
buy more cats
Re:So how do we... (Score:2)
I need a new keyboard now. This old one doesn't work so well now that it's full of coffee...
Schrodinger's running cat (Score:2, Informative)
Now they replaced the inhumane process of killing cats with just letting the cat hit Enter to run the program (instead of killing it). So now instead of "so
Re:April Fools? (Score:3, Funny)
Narratordan
Re:news? (Score:2, Interesting)
Elitzur bomb-testing experiment [Was Re:news?] (Score:2)
OK, but first take a look at Elitzur-Vaidman's bomb testing experiment [wikipedia.org] which (I think but not sure) is the predecessor of these counterfactual repeated measurement experiments. .
.
.
.
Are we done? So, if you read the bomb testing experiment above, you'll see that you have a pretty good chance of detecting a live bomb without actual
Re:news? (Score:2)
Thank you.