Page 19 - Winter 18-19

looks like that from propagation of waves (as in the figure above). It was shown that the single electron or photon will go through both slits and interferes with itself.
You can imagine this was quite a challenge to the thinking of physicists. What could be a possible solution?
What was finally decided as the correct way to understand this is that the electron is not being transmitted as either a solid physical particle or an electro-magnetic wave. Rather what is being transmitted is a “wave of probability.” What does this mean?
The mathematics of quantum physics predicts that an electron (or atom, or parts of) does not really exist in our time/space continuum until it is detected. What is there is the probability that it may appear there when observed. It could just as well appear somewhere else (though with less probability).
where then does the electron come from?
In what we refer to as “The Big Bang” all the matter of the universe was brought into being. Though much of it did not stay around, some did. This we know as the physical matter of our universe, including electrons. The source is what is called the “quantum vacuum.”
The word “vacuum” sounds like it is empty and in a sense this is correct. It is empty of anything detectable in our universe. However, there exists a dimension from which all things spring and it has been found that the so-called vacuum is teeming with particles appearing and disappearing constantly. They come in pairs — positive and negative — and almost immediately are annihilated. That the physical substance we know came from outside the time/space continuum is a tremendous discovery.
That the quantum vacuum is still active, seething with particles constantly appearing and disappearing shows us how very active the universe is.
The Probability of Experiencing
If we come back to the 2-slit experiment and now know that what is being transmitted is the probability that the electron or photon will be detected at some place, what determines if they are to be sensed? In more recent times it became possible to investigate this further. The technology allowed the monitoring of the transmission of electrons or photons. It became possible to detect what was moving from the source (such as the electron gun) to the screen. Was it a particle or a wave?
Oddly when this was done it was found that the outcome (wave pattern or particle pattern) depended on the presence of an observer. If the experiment did not have a detector turned on the result on the screen was the pattern that resulted from the propagation of the probability wave.
However, it the detector was on, then it was particles hitting the screen. We see this difference in the two pictures (over page) which show the patterns when observed and not observed.
Again, another shocking outcome.
These experiments brought in the influence of a conscious observer determining the outcome. Not where physicists were expecting to go!
“If we set up a system to monitor which of the two slits that the photons are going through, we always see individual photons passing through just one slit or the other — and in that case we do not get an interference pattern on the far screen. The behavior of the photons at the slits is changed by how we choose to look at them.”4
This was odd enough that it prompted even further attempts to understand the phenomenon and in 1978 the physicist John Wheeler5 suggested as a thought
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