Whats the deal with quantum computing

[Arkitech]

About a year ago I glanced briefly at an article which talked about how IBM had been working on a new computer that would be based on quantum mathmatics.

What exactly is quantum mathmatics and why would it be useful in a PC?

 

[TripleJ]

WARNING: THIS WILL HURT YOUR NOGGIN!

Quantum computers are really weird, because quantum mechanics is really weird. Quantum mechanics is what happens down in the world of the really small, where the atoms live.

But let's get real, and think about the Earth going around the Sun. And then compare it to the conventional image of an atom, with an electron orbiting around a central core, or nucleus. You would think that the electron would be just orbiting around that central nucleus. It is, but that electron is also everywhere else in the entire Universe at the same time!

For another example, think about something normal like a rock or a stone. You know exactly where it is and, if you leave it somewhere, it will stay there. You can pick it up very exactly, because you know where it is. You can change the shape of that rock into most other shapes you want, and you can even throw that rock accurately to anywhere you wish within throwing distance.

But if you think "quantum", all that accuracy goes out the window. If you try to look at a quantum particle, the mere act of observing it changes it into something else. And don't even think about trying to touch it. You can't make your quantum particle have a specific shape, except by getting it to run between a few wave guides. And even in that case, you will get a fuzzy shape, not the exact one you wanted. You can't "store" a quantum particle - it will just evaporate. You think that you might be able to make your quantum particle go from "here" to "there", but at the same time as it is "here" or "there", it is also "everywhere else in the Universe at the same time".

In the computer logic that we use today, a normal memory element is either "on" or "off". But a quantum memory element is truly schizophrenic. It is both "on" and "off" at the same time, as well as being in all the possible states in between "on" and "off". This fuzziness is what makes a quantum computer so powerful - its ability to be in all possible states at the same time. When you use a quantum computer, you are also using a whole bunch of other quantum computers in other universes at the same time!

We haven't actually built a quantum computer yet - but we have proved that it is not impossible. And almost every month, another scientist somewhere in the world makes another advance that brings us a little bit closer to a working quantum computer.

The great attraction of quantum computers is their immense power. Now here is an example which is relevant to you, if you have ever used a credit card, or had something bought for you with a credit card. Think about a number which has 100 digits in it. This is a really big number. The number which tells you how many atoms there are in the Entire Universe has only 80 digits in it!

Now try to work out which are the only two numbers which, when multiplied together, will give you that original 100 digit number. This is called "factoring a 100 digit number". It's a real and useful problem. Most computer security systems use exactly this logic to protect credit card numbers.

My young children thought that a fast computer of today could solve that problem in less than a second. They were very wrong. In fact, this is a very difficult problem. It would take about 500 of today's computers about 5 months to solve that little problem. And to "factor a 250-digit number" would take the best part of a million years. But a quantum computer could factor a 250-digit number in seconds! Now you can see why quantum computers are so attractive.


Source: Dr Karl

Spun out, huh?

 

[bigbootydaddy]

my head spun twice

 

[Elledan]

Where is the detailed story?

 

[Arkitech]

whoa thats very impressive and a bit strange

 

[TripleJ]

You wanna know more? You're insane buddy!

That's all I know on quantum computers. I know that Sydney Uni is trying to develop a quantum computer. Maybe try Sydney Uni's site. There are about 14 teams around the world trying to do it.

 

[V]

My head didn't spin. Maygbe I should get into quantum mechanics. It sounds so interesting.

 

[Cattlegod]

basically it is this. the quantum computer is given a problem to solve, the way it solves the problem is by looking at all of the possible solutions at once ( an infinite number ) and the correct solution *pops* out.

here is an example, say the constant of the universe was 5 and the equation to solve it would take a bzillion years for a normal computer to calculate it. well a quantum computer looks at it like this

_____5
...1234 678...

it looks at the equation and the answers from negative infinity and positive infinity and the correct answer pops up, and it can easily say, "hey, that one is the correct answer because it is popping up".

as far as the details about how it exactly works i do not fully know, but that is the general idea.

EDIT: adjusted the 5 so it was above the gap

 

[TripleJ]

Imagine the possibilities of such a computer! They would be endless. You could figure out some of the most complex things imaginable. Imagine if you were the one who invented it! Move over Intel . That'll be the day.

 

[TripleJ]

I think they reckon it works by being able to control the orientation, movement and spin of electrons. Obviously that is an extreeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeemly simplified way of looking at it.

 

[Elledan]

TripleJ, I think you forgot an 'e'

And yes, that was extremely simplified

 

[TripleJ]

No Elledan, it wasn't an extremely simplified way of looking at it, it was an extreeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeemly simplified way of looking at it . And where abouts does that 'e' go? Before the 3rd one or was that the 27th one?