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Basicly a computer can only work in two states, that being On or Off. The off state is considered 0000 0000 in binary, a logical 0. The on state is considered 1111 1111 in binary, a logical 1.

Now with a quantum computer, you can have two or more states. That being, the computer can be either on, off, or on at the same time. This allows the computer to not only save power, but it also allows it to do very complex calculations at twice the speed of a normal computer.

I suggest taking a look at [url=http://http;//www.qubit.org"]www.qubit.org[/url] for more information. Dont hesitate to ask further questions considering this is my cup of tee. ;D

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beyondsociety was a bit oversimplifying things there. It's not about the computer being on, off, or both things at once...

"bit" stands for "binary digit" - binary, because there are only two states it can be in.

Quantum mechanics is about "metastates" (or "superpositions"), i.e. a "quantum digit" (hence qubit) being true, false, or in metastate. Only by determining the state of a quant, you fix it to either the true or false state - you can't "read" a quant in metastate. When it "senses" that it's being "read", the quant "decides" which state it is in.

The rest is really weird mathematics.

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Perica wrote:
Alright, so what you're saying is that a qubit starts out in a "metastate" and if read before being initialized to either 0 or 1, one of the two is randomly selected?

No, it's much more complicated than that. And it's really hardcore physics...

How will this "metastate" advance processing technology so much? How can the processor even use a qubit if it's in two states at once (even though I don't understand how this is possible), wouldn't it be totally useless if it's in both states?

That's why I said there's heavy math theory involved. A quantum computer is a totally different beast than your average CPU of today, and the logic involved is equally different. We're well outside the realm of boolean logic (true / false), Turing machines, or von Neumann architectures here - and that's why this technology can do certain things at speeds undreamed of before. In theory, mind you, these thingies are still far from leaving the labs.

Lastly and most importantly, how will this new technology effect programmers? Will the current C/C++ programs that are written with portability in mind be able to be ported to this new technology?

Funny notion. No, you cannot "port software" to quantum computers. Our programming languages assume boolean logic, which quantum computers just don't provide.

I think the term "computer" is misleading here. We are speaking of a completely different technology, not just another CPU type that's faster than existing ones. The only similarity between a PIV and a quantum computer is that both can be used to do maths.

Quantum algorithms are nothing Knuth has ever written about in his books...

maybe one can best abstract/describe a quants behaviour with the one of neurons?

Or other: how would one *program* as given set of neurons?

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let's say for instance you want to crack a code. A quantum computer would have the ability of testing *all* the keys at the same time (since the complete metastate ???? covers both 0000,0001,0010,0011,0100,0101 ...

So you just do the computation of Decode(Coded,????) and the output is the "quantum superposition" of all the results ... somehow ... and this superposition contains the decoded message with the proper key.

However, you still have to "sense" the real input without destroying the 'superposition' by 'probing' it ... You may figuring it as a pencil in perfect balance in a perfectly closed environment. As long as you leave it quiet, the pencil may be standing on its lead, neither falling left or right (which almost exactly correspond to the 'meta-state' ?). As soon as you enter the room to check if the pencil is fallen left or right, you disturb the environment and thus the pencil immediately fall ... so you cannot even know it was in '?' state before ...

Quantum computers nowadays barely have a handful of Qbits, however, and look more like a fusion reactor in a SciFi movie than like a computer ...

Perica wrote: So does that mean that all current knowledge of programming would be pretty useless as quantum computers are a whole different ball game?

Correct. The algorithms that can be used are vastly different.

I doubt it though that even if this new technology is used in processors (whenever/if ever it will be possible) that the current silicon processors will die out...

Certainly not. There are many areas where the quantum computer of tomorrow couldn't hold a candle to a desktop CPU of yesterday.

Just on a last note though, does this quantum technology store all data in binary?

The input data and the output data are binary, so they can be fed and retrieved by "normal" computers. That's the current "state of the art" in the labs where people toy with this concept. (Note that it's also "state of the art" to play with half a dozen qubits or so, just to show how "young" this technology still is.)

So if the quantum technology can not perform boolean logic then I get the impression that it doesn't store numbers in binary...

Storage and logic are two different parts.

Perica, it sounds like you've missed out on some of the most basic lessons of information technology - boolean logic, von Neumann architectures... that's rather strange for someone so interested in the field. May I ask how old you are?

Hi

I thought a von Neumann architecture machine was simply one that kept it's code and data in the same memory, with Harvard architecture being in seperate code and data memmories.

srg

srg wrote: I thought a von Neumann architecture machine was simply one that kept it's code and data in the same memory, with Harvard architecture being in seperate code and data memmories.

In a nutshell, yes. But with a quantum computer as of today, you don't have "code", and no ALU either, to not even speak about address busses and control busses... just a bunch of quants you're handling in some way. You just don't know what architecture will come out of it in the end.

And note that many x86 operating systems use different segments for code and data... does that make your desktop a Harvard architecture?

Very soon silicone processors which have certain heat restraints will hit a brick wall because they just won't be able to run more processes through the processor without burning it up, when that happens, and the price of manufactured diamonds becomes low enough, we will then see a new revolution in computer technology as diamond computer processors will be able to handle any heat and processing speeds will once again start growing exponentially.

With these new computers we will then be able to take control of this whole quanta idea. We can toy with it now and recently, within past couple of months, they got a quantum computer to calculate 3 X 5 = 15. So while progress is being made it is still in it's infancy and mostly theoretical.

But then again there is the idea of the quantum virus, the brown goo that devours the Earth. Not all positives I guess.

I think, however, that thatt is a couple of revolutions away so there's no reason to fear the goo yet.

cloudee1 wrote: We can toy with it now and recently, within past couple of months, they got a quantum computer to calculate 3 X 5 = 15. So while progress is being made it is still in it's infancy and mostly theoretical.

What they did was not calculate 3 * 5 = 15, but 15 = 3 * 5.
That's a huge difference, and is one of the reasons to fear a too fast breakthrough of the quantum computer. Encryption techniques rely solely on the fact that, with the current computers, it's impossibly hard to factor huge numbers. It's been said that with a quantum computer, this could be done in a matter of seconds. It's very important to realise this, and to be prepared.
Btw: If I remember correctly, the factorisation of 15 was done at least two years ago. News on the progress of quantum computing has since been an alteranation of successes and failures.
Some say it'll be the biggest thing since sliced bread, others say it won't be what we're hoping for.

An interesting possible use for quantum computers that gets mentioned a lot is to make tiny quantum automata and insert them in the human blood system, where they'll travel through the body to search and destroy cancer cells.