Quantum computing.

[too-open-minded]

I was just wondering how it worked and related to the quantum world of physics. Anybody care to explain in lay-mans terms? Wikipedia was a bit over my head on this subject.

[Bill Angel]

That's a challenging question to answer, because the functioning of a quantum computer is based on subtle and non intuitive aspects of quantum theory. Not surprisingly there are quite a number of videos over at Youtube in which experts and students attempt to convey the principles of quntum computing to a general audience in videos running less than five minutes. I don't think any of them succeed all that well, but you might watch a few of them to clarify which of the issues pertaining to quantum computing you are most interested in discussing.

Edited August 14, 2012 by Bill Angel

[too-open-minded]

From what I understand they are trying to use particles and energy to process information? I guess they would record the behavior of the happening and use its constants as measurement intervals instead of BIT's or processes of 1's and 0's?

 

I'm probably wrong but is that anywhere close?

[imatfaal]

Shtetl-Optimised This is a great blog about quantum computing. I will dig out a few links that explain some simpler ideas. Scott's explanation of Quantum Computing and the QUantum Fourier Transform was amazing - even I managed to get my head around it after a few reads.

 

Shor, I’ll do it This is my favourite - note that one of the very positive comments is by Peter Shor

 

 

[too-open-minded]

One day I hope to be educated enough to understand that lol.

[Bill Angel]

Here's an interesting article I came across. While it really isn't a basic introduction to quantum computing, it does discuss the technological challenges one group is struggling with in order to implement a quantum computer logic gate.

 

http://www.technologyreview.com/view/427998/a-photonic-c-not-gate-breakthrough-for-quantum/

[Mark Ian]

the thing I can't get over is that a qubit supposedly is so different to a normal bit. The only real difference I see is that qubits have 3 states and a bit has two states of means of storing information. The more trivial quality of quantum computing I see is that its so much smaller than the conventional computer transistor- or is there more to it?

[Greg H.]

the thing I can't get over is that a qubit supposedly is so different to a normal bit. The only real difference I see is that qubits have 3 states and a bit has two states of means of storing information. The more trivial quality of quantum computing I see is that its so much smaller than the conventional computer transistor- or is there more to it?

 

The major difference isn't just that it has one more state of storage, but that the new state is actually both options at once. Consider it like this:

 

If we just added a third state to standard bits, so that we could plug in a 0,1, or a 2, all we've really done is make computers work on base 3 instead of base 2. If we take an 8 bit register and fill it full of 2's, we still get a single discrete value.

 

With an 8-bit register of qbits all in the third state, you do not get a discrete value; rather, you have all the possible values at once. This is fundamentally more information than a standard 8 bit binary (or even ternary) register. In theory, you can take this all possibilities probability wave, collapse it, and come up with the single answer to your calculation.

[Mark Ian]

I have read the wikipedia article on Qubits in which is stated that the possible states a qubit can take can be represented as a position in a bloch sphere. This sphere, a visual representation of the superposition basis state, should be able to hold more than just 3 bits of information. Depending on how accurately the position can be measured, I would assume that a qubit could hold much more information than a mere 3 bites. Furthermore there is a table right under the subtopic physical representation, each point under 'Information support' being a possible bite (giving you at least 13 bit). Plus the probability amplitudes can be expressed as complex numbers increasing the information capacity by a factor or two.

 

In theory, you can take this all possibilities probability wave, collapse it, and come up with the single answer to your calculation.

I do not understand this.

[Greg H.]

I have read the wikipedia article on Qubits in which is stated that the possible states a qubit can take can be represented as a position in a bloch sphere. This sphere, a visual representation of the superposition basis state, should be able to hold more than just 3 bits of information. Depending on how accurately the position can be measured, I would assume that a qubit could hold much more information than a mere 3 bites. Furthermore there is a table right under the subtopic physical representation, each point under 'Information support' being a possible bite (giving you at least 13 bit). Plus the probability amplitudes can be expressed as complex numbers increasing the information capacity by a factor or two.

 

 

I do not understand this.

 

Honestly, I do not understand it that deeply, only what I have read. If you're interested I can recommend A Shortcut Through Time, by George Johnson. It's a good introduction to the idea behind quantum computers and how they should work (in theory).

[Mark Ian]

Thanks, i just might read that book. The field of science I want to work in (protein design) deals with quantum mechanics. All the books I've read about seem to be at post graduate level, if you can suggest a book on quantum mechanics that is easier to digest, that'd be great! (or anyone)

Edited August 24, 2012 by Mark Ian

[imatfaal]

Mark - what sort of level are you at?

 

For opening levels I could not recommend anything more than

 

How to Teach Quantum Mechanics to Your Dog

 

If you are looking for some maths with your ideas then perhaps other can advise you better. I think the Feynman lectures will be recommended

Edited August 24, 2012 by imatfaal
bad phrasing

[Mark Ian]

zero-ish. Ill go buy the book on monday. I started reading quantum physics for dummies, but it quickly became apparent that my math skills were insufficient, so I decided to start to patch up my calculus yesterday (i never directly took a calc class). For now I think the books will last me till fall, if not longer. thanks a bundle for the suggestions

[Delta1212]

I do not understand this.

This is not my best analogy, but think of it like this:

 

Finding an answer to certain problems on a computer is like trying to find the type of coin that fits in an unlabeled coin slot. The best method is really just to try each type of coin in succession until you find the one that fits.

 

With a quantum computer, you'd be able to use a special type of coin that was every type of coin at once. Then when you put it in the coin slot, it would lose all the types that don't fit so you're just left with the correct coin on your first attempt.

[too-open-minded]

From what I get out of this, and I might be wrong. I have no knowledge of computers and only know about bits because of quantum computing.

 

Regular computers use bits to process information. bits is binary code. Theirs a 1 and a 0. Those ones and zeros stack up to represent things.

 

With qubits having a 0, 1, and a 2; now this reduces what stacks up to represent things. Codes are shorter. Processing doesn't take as long.

 

Now theirs a 0, 1, 2 but what exactly are they representations of? If you measure a subatomic particle under certain conditions like temperature, we should be able to find some constants in their behavior in correlation to differences in their environment.

 

We use these constants per change in environment to represent something. This way we literally have particles and atoms processing information and reducing the process time we have with binary code processing.

 

 

Is that anything close?

[JohnStu]

Quantum computing? There is a prototype version of it in my lab. The semiconductor (is a protein) has 6 states, so it will be based on 6 digits if only I could find a way to mass produce these proteins cheaply and put them to the proper places.

[too-open-minded]

How does the processing work?

[elaw82]

I agree! These concepts are easy to follow but as soon as we get into the math I get lost.

 

One day I hope to be educated enough to understand that lol.