Monday, May 7, 2007
Quantum Mechanics-An attempt to demystify it
Niels Bohr, one of the founders of quantum mechanics once said,
And anyone who thinks they can talk about quantum theory without feeling dizzy hasn't yet understood the first thing about it. If it hasn't profoundly shocked you, you haven't understood it yet.
Certainly, quantum mechanics is one of the most bizarre topics ever conceived by physicists. From particles that are called "strange particles" to the probability wave function, many people have expressed the urge to vomit when studying this topic. The idea that light can be both a wave and a particle is certainly a bit difficult to express. Perhaps we should call light as a "wavicle"? Or maybe a "partive"? A particle is something is capable of travelling in space. Or we should say capable of translation in motion. For a wave, there is no such travelling. Each particle in a wave oscillates about its mean position. It is not going anywhere, for its average displacement is zero. Yet the wave 'moves' from one place to another. Actually, why is so mind-boggling to think about light as a wave and a particle? Already, the idea that light is a particle is wierd? A particle is a point mass. It has no volume. So light particles have no volume. They are supposed to have no mass either. Its just a combination of oscillating electric fields and magnetic fields.
Here's a real trick to be both smart, and get away with not doing homework! Say, if the Planck constant were to suddenly increase in magnitude to be equivalent in magnitude to the graviational constant, then your homework may suddenly disappear when you are not keeping an eye on it. After all, you can invoke the de Broglie equation to calculate the de Broglie wavelength of your homework. And then you can apply the Schrodinger wave equation on it, and get the probablity wave function for the piece of homework. If you put your homework in your file, there is quite a chance for it to 'tunnel' out of your file, and your homework may be lost!
Some other points for you to comtemplate though. How does a particle after going through the double slit experiment still result in interference patterns? 'Classic' quantum theory says that the probability wave function of the particle interferes with itself, by going through both holes simultaneuosly. Perhaps we can just explain this in classical mechanics? Say, the slits actually deviated the path of the particle? The gold foil experiment comes into mind. Anything could have caused the path of the particle to be deviated. Gravitational force, electrostatic force, etc.
In the photoelectric experiment, perhaps the same thing can be explained with classical mechanics too? For example, light strikes the surface of the metal. The electrons on the surface interacts with the light wave to form a standing wave. At the correct frequency, resonance occurs. And enough energy is transferred to the electron to allow it to be escape. Hows that compared to the idea of the photon knocking out electrons?
Questions anyone? Or answers perhaps?




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