Krista's Coding Corner

14.04.2012

Quantum computing

Have you seen Hitchhiker’s guide to the galaxy? If not, you should see it. The movie gives some excellent insights to the computing world. (Okay, the books are awesome too :P Just giving you an easy road here ;) ).

In the movie / book they find out that *spoiler alert* the answer to the ultimate question of life the universe and everything is 42. This answer is created by supercomputer Deep Thought, specially built for the purpose of answering this question. You can understand how people, who were wishing to know the purpose of, were like WTF!!?!!! after hearing the answer 42.

But this is reality, in some ways, even today. Quantum computers give answers such as that number 42. It may be really tricky to understand the answers... And good question is always: what did we actually ask? :)

So, what is a quantum computer? First of all, regular computer is like a billiard pool table. We can put some balls on it, in certain positions and we can hit one (white) ball which (hopefully) collides another ball and so on.

Our input is hitting the (white) ball in certain spot with certain force. Then the ”magic” happens: the other balls may move and also some collisions may happen. After that we see the output: where balls are. Different positions have different meanings. Learn math and physics kiddoes to count where the balls will go ;)

But this billiard pool table can also give you answers. And if places / forces / masses etc. have different meanings than just place / force / mass, you may calculate many other things as well. Not just some ball positions considering where we had hit them.

How this has anything to do with quantum computers? Well, quantum computers are like these billiard pool tables BUT the balls do NOT behave like in Newton’s physics. This means that we take probabilities into account and there is not just one path to go. Why? Because in quantum computer we don’t have regular balls, we have quanta. And they prefer being a bit more complex people than balls.

When we hit the quantum, it doesn’t have only one direction to go. It has several. Other directions are more likely than others. And some random other quantum elsewhere may also take into action even we are not hitting them. Believe it or not.

Vocabulary:

qubit: ==quantum bit. This is equivalent to the regular computers bit. But it isn’t the same thing. When regular bit can be either 0 or 1, qubit is 0 with probability x and 1 with probability y. So, it may be 0 and 1 in same time (or neither one of them also). We can know for sure only if the qubit is measured but.... then we will have only result for certain specific time slot. It may change into something else less than a second.

Qubit has some similarities with S. S. Heart of gold, which is a space ship in the movie / book I was talking about. It has a Infinite Improbability Drive that is faster than light -drive. To keep this short, I just link Wikipedia :) Here you go.

Sorry, I have to continue writing this at some other time as I have terrible fever right now... And I’m not thinking so clearly :(

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