keskiviikko 22. lokakuuta 2014

On special relativity and matter waves.

I haven't really figured out why Einstein's E = mc^2 is probably the most well know physics equation. This equation, widely know as Mass–energy equivalence has been popularized so well that it can break down cultural and social barriers. Even if a person has no true interest on physics or sciences in general it is likely that he or she recognizes E = mc^2 formula and sees it as reference to something ingenious.

Despite of being as recognizable as Mona Lisa, mass-energy equivalence doesn't open up as a concept to most of the people even though the principle in it is pretty straightforward. Mass is a form energy. There you have it. According to Einstein, it is possible to transform energy into mass and annihilate mass into energy. So it's not like even physicists would need it in every calculation they make.

λ = h/p equation isn't considered common knowledge in a same manner that mass-energy equivalence is. Maybe it's because it has that strange letter λ- Lambda in it. Whatever the reason is, this second equation, know as The de Broglie Equation, could be arguably as momentous as Einsten's.

de Broglie's equantion main principle is that particles have wavelength λ. Greater the momentum, shorter the wave. This was quite revolutionary hypothesis when first proposed in 1924. Apparently there was not any proof of particles having wave properties at the time, but de Broglie had intuitive thought that if light has both wave and particle properties, electrons must have them both too. He came up with his equation which he published in his thesis and his hypothesis was later proven to be correct.

Why aren't there waves everywhere?


I don't know the rules of softball, but the ball never flew as a wave during
the time I observed game in Central Park, New York 
So de Broglie thought matter are waves and Einstein thought mass is a form energy. How this sum up together? Classical particles are far more difficult to model, as they aren't well located lumps anymore. Instead, particles with mass are spread out in space like waves in ocean since mass is form of energy. Really crazy part is that mass moves as a wave in a vacuum. So matter is like waves without ocean.

This of course conflicts with everyday life we all experience. We don't see billiard balls (or softballs) move like quantum waves. They are simply too complex to act that way. It was for long thought that quantum rules only apply when we measure very small particles, like singular electron. Researchers have eventually succeeded to perform the double slit experiment with rather massive molecules, like fullerene. It seems that quantum rules don't apply in matter of size but rather on how well particle is isolated from other particles or in the case of molecules, also from itself since molecules have multiple atoms.