Monday, 31 January 2011

Quantum mechanics - an introduction.

I thought I'd tackle another hard science subject of the future - quantum computing. But I realized you first have to know about a whole new way of thinking. Thinking in quanta.

So, first comes quantum theory. 

Best known -or better: least unknown- is the field of quantum mechanics.

In essence, quantum mechanics is just a mathematical description on how matter and waves (read: radiations like light). On macroscopic scale, these effects are seldom observed, but at extremes (microscopic, or very high or low temperatures or energies) some odd observations can be made.
Max Planck observed that some physical quantities can only be changed by discrete amounts, called quanta, which are multiples of the Planck constant, instead of varying in a continuous way.
A bound electron, for example, can only change within certain energy states. The difference in energy between these states is the quantum involved.

A second observation made was that the matter and wave-like behavior seem to overlap. A particle (like an electron) can behave like a particle, and eg. collide, but also has a wave-like property, and can therefore interfere with other particles/waves.

A third effect involved is Heisenbergs uncertainty principle, where you can, on microscopic scale, not say what the total characteristic of this particle/wave is: if you observe it as a particle, you wont get information on it's energy, but only on its (probable) position, and vice versa: if you observe the wave, you can get info on everything but the position. You see the dilemma. It's like a spooky thing that forever slips through your fingers.

(I know, some physicists will now start grumbling and protesting. But I'm not writing a college text here. I'm trying to explain the whole thing in less than 400 words....)

The previous is called the wave-particle duality. Physicists tend to describe a particle as a wave packet.
The rest is higher mathematics, witch I'm not totally familiar with, and interested persons should start a degree in physics to understand this.

The biggest consequence is that it is like a particle can be at the two places at the same time, or have different 'appearances at the same time. And this stays, until the moment someone comes in and takes a look at it. and suddenly, PING!!!! its just in one place, one state, behaving like we know it. 

De concept of being in many places and/or states at the same time is important, as long as there is no observer. It means nothing is definite until somebody takes a better look at it.

The consequences are enormous, also on philosophical terrain. Does nothing exist (in one definite state, that is) if there's nobody around?

Mind-blowing.
But as up to today, nothing really challenged the theory, and observations have been made that suggest the thruthworthiness of the hypothesis.


More tomorrow.

33 comments:

  1. I've got a hoodie that reads "Heisenburg may have been here".

    No one ever gets it.

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  2. Thanks. I feel a tad smarter today reading this.

    Following. Keep up the insights.

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  3. @ Vapor - at least it's not a thong that reads "Schrödinger's Pussy".

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  4. The older I get, the more I become interested in physics and science. I should have been more curious at school :/

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  5. I'm getting educated pretty hardcore right now, awesome post.

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  6. wow I love quantum theory, can't wait for your next post

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  7. a great and short explenation what quantum mechanics is about

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  8. good stuff man!

    your friend,
    ectomorphmuscle.blogspot.com

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  9. Very refreshing compared to most of the other blogs out there, good work.

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  10. wow you made me think to hard, i are in agreeance with brut and mranthrope

    blundersfrom6foot2.blogspot.com

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  11. all in all dude a great condensed review of quantum mechanics!

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  12. I was into quantum mechanics two years ago, read a lot of stuff, even understood some of it, and on New Years Eve I came up with an own theory. I was pretty high on weed at that time, so I might turn the universe inside out when trying to implement it. Sorry in advance!

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  13. Quantum Theory has some pretty interesting sides to it

    looking forward to more posts by you

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  14. "nothing is definite until somebody takes a better look at it."

    mind = blown. i need to go back to college.

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  15. Excellent explanations. I wish I had more to add here, but I sadly am not versed well enough to comment one way or another. :/

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  16. I love learning about the principals of physics but I don't think I'd make it as a career.

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  17. Good article, w8ing for more. Cheers

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  18. I love this stuff, the idea of a particle being in two places at once just blows my mind. It just makes me wonder how much more there is to discover about the world around us that we have no idea about. Keep it up, these articles have sparked my interest

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  19. great post, very interesting quantum theory..

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  20. holy crap, you lost me at "introduction"

    just kidding but wow, complicated stuff!

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  21. great post. I'd like to see some more posts on quantum theory/computing. It's a subject that I find kinda interesting, but not enough to really look into it on my own.

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  22. lol i saw this was one of your posts and i juat had to compare it to my basic intro to quantum physics.
    in the spirit of the quantum world i'd say our explanations are complimentary :)
    this is an old post... so if no-one reads this comment did i really write it?

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