Quantum Computers. Options

[Shock]

Ever since it was introduced, Moore's Law has been holding itself up. It states that every two years the abilities of computing hardware doubles. However, this is still a 2X straight function, and will not make for revolutions. One of the most promising ways to break Moore's Law with a high derivative, and probably one of the only ways, is Quantum Computing.

I created this thread not only to discuss it but also to show that recent developments in Quantum Experimenting have gone really fast. Last month for example, a prototype solid state quantum processor was already utilized for small calculations, after the first prototype device of quantum computing was developed in 2007. Think of it as reinventing the computer, only in a completely different way.

The basics of quantum computing compared to classical computing, in short:

A quantum computer works by something called the quantum state. In fact the quantum state is based upon probability, and the wavefunction is the function which, for every possible quantum state, defines the probability for that state. This is something you cannot observe - you can factually only look if the particle is in one certain state, and when you do that on that moment, this single state you are looking for is also 'chosen'. The answer to your observation would then simply be Yes or No. You cannot look at a qubit and find out what state it is in, but only look for a state and then by means of probability, you will get your outcome. This outcome is dependent off the wavefunction which is evaluated for the specific state, with which the wavefunction collapses.

In terms of qubits, with two states (like normal bits 0 and 1), there is a chance that it will be 0 and a chance that it will be 1. You can manipulate qubits, so that it for example will have a 70% probability of being 0 and 30% of being 1. You cannot ask the qubit ''what is the chance of you being 0'' , but only ''are you 0''. On that moment the qubit picks a state, and it 70% of cases it will say yes.

The beautiful thing about quantum computing is that the individual quantum bits aren't independent. In other words, with every two qubits the chance that qubit A is 0, also depends off the other qubit. This is because of the property quantum entanglement which I won't clarify here simply because I can't. With two qubits there are four possible states: (0, 0), (0, 1), (1, 0) en (1, 1). Every one of those states has it's own specific probability. With 3 qubits, it will be 8 different states, and with N qubits that will be 2^N different states. This is why the power of a quantum computer increases exponentially with the number of qubits.

Three classical bits can only be in one state at the time, 0 or 1 and that is where it can perform it's calculations with. With quantum bits, you can perform calculations on all different quantum states because the qubit is in a superposition of all the possible states. So you can perform parallel calculations on all the states at the same time!

This is my basic understanding of quantum computing, but I'm still not sure about whether I understand it all right.

The large problem in Quantum Computing to day was the preservence of the Quantum Bits for longer periods of time to utilize them for more complex calculations. Last month, a giant leap into fixing that problem was taken by the same scientists who made the quantum processor, they extended the lifetime of qubits by a factor of thousand, which made it possible to read the qubits accurately after calculations.

More problems come with increasing the number of qubits. The quantum processor the the American University still uses only two qubits. With more of them, it becomes increasingly hard to engineer the proper interaction between all of them, and you risk losing the information as well to the environment. This last obstacle is one major problem that puts them away from putting quantum computers in your X generation smartphone, as a way will have to be found to make qubits only affect eachother and not the environment.

I'm not uncertain about the potential and revolution of quantum computing, though

This post has been edited by Shock: 7 Jul 2009, 12:56

[Pickysaurus]

Wow!
This all sounds like a Sci-Fi film.
Doesn't it mean something is everything/everywhere if it is Quantum?

[Shock]

Well i'd rather keep this topic on the branch of Quantum Computing, not everything that relates to Quantum Mechanics.

[Pickysaurus]

Ok, well it all sounds slightly odd to me.
That the computer has to guess what the binary code is :S

[beefJeRKy]

So I'm guessing from this that a classical microprocessor will be needed to allow the more advanced quantum computer to function eh? Hybrid computing. SOunds genuinely interesting and like something I would specialize in.

[Shock]

So I'm guessing from this that a classical microprocessor will be needed to allow the more advanced quantum computer to function eh? Hybrid computing. SOunds genuinely interesting and like something I would specialize in.

I don't know really. I only just have basic understanding of how the actual computing works. I have been told a quantum computer in it's current theory cannot do everything a transistor based processor can, but it would be pointless if there is a classical computer required for it to function, the bottleneck would be enormous.

[Pickysaurus]

So does this new tech have the potential to be more efficient than current PCs?

[beefJeRKy]

So does this new tech have the potential to be more efficient than current PCs?

No no. This is more likely to be useful for scientific applications like the earliest computers were and as supercomputers perhaps. However, nanocomputing is something we will likely experience soon as quantum tunneling begins to affect microchips manufactured on a process smaller than 32nm.