Blog of Veikko M.O.T. Nyfors, Hybrid Quantum ICT consultant

Quantum Mechanics demystified, a try

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About polarization

Most people know about polarized sunglasses, how one can see more clearly with them in certain glaring situations. Also people might know on high level how polarization works, by passing through light (photons) with waves vibrating only to one direction. Having two polarizing films perpendicularly one after each other, no photons will pass through. Etc.

But why am I talking about this?
I am trying to understand the nature of light and specifically how/why interference patterns are created in double slit experiments. Even more precisely, why does interference patterns vanish once an observation is made to detect through which slit the photon is traveling.
One of the methods used to observe is to use polarizing film.

To start with, let’s first talk about why the photon reflecting form water surface is horizontally polarized. If the angle between the reflected and the refracted light wave is 90⁰, reflected light will be polarized. That has been empirically proved. But why is that?
It has to do with atoms on the surface of the reflecting material, more specifically with their electrons. Incoming photon interacts with one of the electrons on a surface atom, causing it to excite. After a very short while electron returns to its normal energy level with emitting another photon. These electrons vibrate or wiggle all the time producing an electric field around, oscillating in corresponding direction. Different atoms wiggling in different directions. Now a photon with it’s wave oscillating in matching direction to one of the electron’s electric field, will be absorbed and a new photon emitted, with the same oscillation direction as the original photon. Now, when we take into account, that TO BE CONTINUED . . .