Friday, May 20, 2011

The Arrival Of The Quantum Computer 1

With the arrival of the first Quantum Computer, much of what we thought was impossible will now be a reality.

The Quantum computer is based on a field of knowledge in science which is still not understood, only utilized - Quantum mechanics.

To fully understand this article, we strongly recommend that the reader watch all the videos posted, since they contain background information that will make the text portions easier.

Kindle eBook
Common Tech Problems,
Windows, OS X

What Is a Quantum Computer?
A Quantum computer is a machine that uses a Qubit instead of a bit.  The advantage of this is that a Qubit can manipulate four times the amount of data as a bit.  Of course to understand any of this, one must have a basic knowledge of Quantum theory.  In the "normal" world that we are use to, an object cannot be in two places at the same time.  To translate this concept into the binary system of a computer, consisting of either zeros and ones, a standard computer chip has a state of either zero or one at any one moment.  Yet in Quantum theory,  a subatomic particle, like an electron has two active states, in order words it could be in two "places" at the same time.  One of its states is along its X or Y axis and the other along its north or south poles.  In practical terms, there is a "mix" of states measured many times to achieve a probability of what states it is in.

We elucidate with a playlist of videos on this idea of what has been known in science as the Wave-Particle Duality Theory.  If you cannot see the embedded video, here is the link:

sphere showing not only
north and south poles, but
X and Y coordinates

Obstacles in Building a Quantum Computer
According to Gildert, the universe is already doing computing at a very efficient rate.  She states as an example the helium atom, "...a single Helium atom is able to compute the spacing of its own energy levels using far fewer resources than our simulation (which may require several tens of grams of silicon processor)."  In her mind, what a Quantum computer is doing is redirecting atoms to compute things that we wish.  To redirect atoms to do our computations requires "extra resources and energy."  She concludes,
...the best way to arranging computing elements depends upon what we want them to do. There is no magic ‘arrangement of matter’ which is all things to all people, no fabled ‘computronium’. We have to configure the matter in different ways to do different tasks, and the most efficient configuration varies vastly from task to task.
Now most who speak of the Quantum computer mention that it will be able to do all things faster than a traditional computer due mostly, to its ability to be able to handle twice the number of bits at the same time as a traditional computer chip.  But this is not the complete picture.  One of the researchers at D Wave, Dr. Suzanne Gildert has spoken about this quite succinctly,
To begin, consider the phrase ‘computational power’. This may seem easy to define. One could use FLOPs (floating point operations per second) as a definition. Or perhaps we could use the ‘clock speed’ of the processor – just how fast can we get those bits of matter to change state? When looking for good metrics for the computational power of a processor, we come across some difficulties. You can’t just use the ‘clock speed’ of your computer. Imagine, for example, that you split the processor it into multiple cores. Some programs might now be able to run faster, even if the ‘clock speed’ was the same!
She goes on to say that our traditional measurements for how "fast" or how "powerful" a computer is depends "...upon what you want it to do."  For a fuller explanation of this point she states,
...the only reason why metrics such as clock speed and FLOPs have been useful up to now is that we have mostly been using our processors to do very similar tasks, such as arithmetic. But the kind of things we want them to do in the future, such as natural language processing and complex fluid dynamics simulations no longer rely on straightforward arithmetic operations.
There is no matter as such. All matter originates and exists by virtue of a force which brings the particle of an atom to vibration and holds this most minute solar system of the atom together. We must assume behind this force the existence of a conscious and intelligent mind. This mind is the matrix of all matter.
Max Planck

Turing Machine Limitations
The Turing Machine, developed by Alan Turing, has been the standard computation model used for generations.  The Turing Machine was "...not intended as a practical computing technology, but as a thought experiment representing a computing machine."  In his 1948 essay, Intelligent Machinery, Turing wrote of an imaginary machine that could compute "...anything described as 'rule of thumb' or purely mechanical."  According to Dr. Jack Copeland, director of the Turing Archive for the HIstory of Computing, some serious misconceptions about his logical computation machine have been made by various authors.  Copeland states,
Turing did not show that his machines can solve any problem that can be solved "by instructions, explicitly stated rules, or procedures", nor did he prove that the universal Turing machine "can compute any function that any computer, with any architecture, can compute". He proved that his universal machine can compute any function that any Turing machine can compute; and he put forward, and advanced philosophical arguments in support of, the thesis here called Turing's thesis. But a thesis concerning the extent of effective methods -- which is to say, concerning the extent of procedures of a certain sort that a human being unaided by machinery is capable of carrying out -- carries no implication concerning the extent of the procedures that machines are capable of carrying out, even machines acting in accordance with ‘explicitly stated rules’. For among a machine's repertoire of atomic operations there may be those that no human being unaided by machinery can perform.
Copeland particularly attacks what he calls Thesis M, which to him is a most common misunderstanding of the Turing Thesis.  Copeland explains this distortion of Turing's view as stated this way, "whatever can be calculated by a machine (working on finite data in accordance with a finite program of instructions) is a Turing-machine-computable."

Dr. Gildert points out another problem with using a Turing machine model for Quantum computing.  She states,
It is certainly the case that you can run any classical digital program on a Turing machine, but the theory says nothing about how efficient its computations would be.  If you would like an analogy, a Turing Machine is to a real computer program as an abacus is to Excel - there is no reason why you cannot sit down and do tour weekly accounts using an abacus, but it might take you a very long time!
She further underscores this point by saying,
We find when we try to build Turing machines in real life that not everything is realistically computable. A Turing Machine in practice and a Turing Machine in principle are two very different beasts. This is because we are always limited by the resources that our real-world Turing machine has access to (it is obvious in our analogy that there is a limit to how quickly we can move the beads on the abacus). The efficiency of a computer is ALWAYS related to how you assemble it in the real world, what you are trying to do with it, and what resources you have available. One should be careful when dealing with models that assume no resource constraints. Just think how different the world would be if we had an unlimited supply of free, clean energy.

If our explanation has not been clear enough, then we will show this playlist of videos explaining the concept of a Quantum computer.  If you cannot see the embedded video, here is the link:

In part two of this series we will cover how D Wave designed their Quantum computer. Stay tuned!

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