Understanding ordinary Physics can be quite cumbersome at times. This can be true even for the brightest of the students. There can be a lot of concepts in various topics that may demand a lot of curious scrutiny even if you are studying the basic ideas. Moreover, a very important subject such as theoretical physics may not only sound difficult but also quite boring to the whimsical adolescent who is slowly creeping out of the teen years and would be soon going to the university. What adds to the misery of the student is that how the subject matter is made to appear so esoteric to comprehend while it is orchestrated.
We had a very nice teacher named Professor Dr. Faiz-ul-Hassan. He used to quote one of his own Swedish teachers while he was a post graduate student that any subject in the world can be explained to any student in a way in which appears easy for him/her to understand. Indeed, Dr. Faiz used to teach very well. I still remember that in his class even the most mischievous of us used to sit and listen to the lectures very quietly and attentively. This is quite remarkable given the lack of interest students generally had in any kind of academic activity. He used to teach us difficult subjects and we used to find them interesting and easy.
A couple of days ago I came across a very nice article that discussed quantum mechanics in the context of human consciousness and its survival after death. The article was quite timely for me because I was wondering how quantum mechanics was connected to consciousness. Even though I could say, “I know what you mean” as an expression in a discourse, I really did not nearly have a clear understanding of superposition and its repercussions on the study of consciousness. Consciousness is recently being acknowledged by science and it would be appropriate to think that any serious student of consciousness should try to understand quantum physics to some extent. It is one of the various ways at looking at the survival of consciousness after bodily death.
So the explanation of superposition was given with the help of a cartoon and I found it very useful, informative and funny at the same time. Even though I had read a little bit about superposition before in the context of quantum cryptography, but I had never understood it so well before. The cartoon is as follows:
If you have seen this cartoon you may definitely have understood superposition and I can bet that you must definitely have enjoyed the cartoon. It just takes a little bit of curiosity to appreciate such work. So giving an explanation of superposition now is rather redundant. I also think that I cannot write an explanation of superposition as nicely as it has been explained by the old man in the cartoon. However, I am going to write down my own understanding of superposition only to gain a little bit of self satisfaction. You can skip this article now if you wish or you may keep on reading it if you wish to leave a nice remark at the end of article.
So what superposition tells us that matter can behave in weird ways. Depending on the circumstances it can retain its physical form or it may also convert into energy. It can exhibit a particle like behavior and it may also act like a wave. This view is endorsed with a so called double slit experiment. What the old man does is that he shows us something with the help of a slit placed between a source of white balls of some sort and a black board on the other. When the balls are fired towards the board some of them strike with the sides of the slit and are deflected away, while a few pass through the slit and form a line-like pattern on the board resembling the shape of the slit through which they passed.
He then replaces the single slit with a plate that has two slits instead and repeats the experiment. As expected what we notice is that two bands are formed on the wall resembling the shapes of the slits. He argues that this is an intuitive result.
In the next stage of the experiment what he does is that he replaces the source of balls with an electron gun. So in the single slit experiment a single band is formed resembling the slit. However, in the two-slit experiment, multiple bands are formed as opposed to the two that were intuitively expected. He argues that this seemingly counter-intuitive result is also intuitive. He argues that the electrons exhibit wavelike motion while traveling towards the plate. As they pass through the slits, some of them reinforce each other and while others annihilate each other through constructive and destructive interference respectively. The result is multiple bands as can be seen on the board.
In the next stage of the experiment he starts firing single electron at a time from the gun. He does so to figure out if the electrons behave differently when they are fired in isolation. What he figures out is that same sort of multiple bands are formed again. He argues that while some electrons are deflected and while some pass through one slit and while others pass through the others, the over all result is a number of bands. He owes this to the wave like nature of electrons as they travel to the board (which is possibly a fluorescent screen of some kind that illuminates as electrons strike it).
The last step of the experiment is crucial. In this step what he does is that he fixes some sort of the detector along side the slitted plated. He does so in the hope of observing the behavior of the electrons as they pass through the slits. To much of his surprise, what he finds is that two bands are formed on the board. He finds this surprising and expects us to be surprised also because he concludes that this time the electrons exhibited a particle type behavior. He concludes that under special circumstances electrons can exhibit either a wavelike or a particle-like behavior. Moreover, he concludes that all matter is capable of exhibiting such behavior.
To us such behavior has far reaching consequences viz a viz human consciousness. It means that in a theoretical sense it might be possible that we humans, which are normally observable as physical beings with flesh and bones, might as well be able to exist other than that too. The question that what was that detector made of that made the electrons so shy that they blushed away from acting like waves demands us to brush up our quantum physics a little bit. Teaching difficult subjects with the help of cartoons like the one above is indeed a very remarkable way of teaching.