If you spend any time at all studying Quantum Physics, then I’m sure you’ve already read numerous examples and claims about the two-slit experiment. In fact, if you’ve been paying attention, you probably already figured out, that this is one of the most important experiments presented. You won’t pickup a book or watch a documentary on Quantum Physics, that the person doesn’t at least offer a glimpse of what this experiment means.
The problem however, arises when only these explanations are entertained. Can there not be others that make just as much sense? Could we be interpreting the data wrong? Does Quantum Physics have to have that mystical quality about it that puts it in line with the unknown, unexplainable, unattainable?
While I don’t purport to be an expert, nor do I claim vast knowledge on the subject, I have read numerous volumes on the subject and have my own opinion. That is the reason for this blog entry today. Not to tell the answer, but to offer up another possible piece of the puzzle in Quantum Physics.
First I’d like to explain the experiment: The two-slit experiment was originally done using sunlight and a few small cards that split the light. The goal was to determine if light was particle or wave. The thought was, that if indeed it were a particle, splitting it up would amount to having a simple shadow on the wall where the light was broken apart. In this case, you can think of shooting small bullets at a wall, with another surface positioned between you and the wall. The bullets could hit everywhere on the wall, except for the small area where you are being blocked.
Now if we expand on this theory and add a second wall, again, we should see bullets hitting the wall everywhere except where our two dividers or blocks are positioned. Seeing this would prove that light acted like a particle (or really small bullets) of light. However, the results baffled everyone that looked. What happened when they added the second slit, caused the shadows on the back wall to cancel each other out and instead of having two slits of light, we had many small strips of shadow and light moving across the wall. The only way to explain what was seen, was that the light was moving as a wave (much like an ocean wave) and that as it passed through the two slits and redefined itself on the backside of our slits, the two separate waves started to cancel each other out and didn’t reach the back wall as a solid line of light and dark, but of back and forth patterns based on the width and distance apart of our slits.
However, our great experimenter didn’t stop there. He next decided that he needed to know what would happen if he were to fire a single electron at the slits. Would he get two slits on the back wall like you’d expect when firing a single bullet through the hole? His thought of course, was yes, he would. After all, how would you get an interference pattern when only firing a single electron? What would it be interfering with?
Things are not so simple in this wonderful universe however, and what we see when firing a single electron through the slits, is that after a period of time we begin to see the same patterns that we saw when sending billions through. Of course it takes a few hours of doing this to get a definable pattern, but they are there nonetheless. But how could this be? What are they interfering with as they move through the slits? This is where all known logic stops and imaginations take over. After all, how could one think logically in relation to such a strange occurrence?
More experiments were designed that tested to see exactly which slit a single electron went through when they fired it. But what happened was that whichever slit they looked through, the electron would enter the other. Like the electron saw them looking and went somewhere else. So next they attempted to look into both slits together to see what would happen and things got even stranger! Now, when looking at both holes, the pattern stopped completely and the expected result of two slits on the back wall showed up. Like, because we looked, the wave pattern stopped.
After many years of thinking about these strange results, scientists decided that what has to be happening, is that the electron is going through both holes at the same time. That it exists at all possible locations at once, and that by us looking to see what its doing, we force it to choose one specific location, therefore canceling out all others and canceling out the wave properties of its movement. That until we look at something, it doesn’t exist in a single location, but in all locations. All things happen at the same time and only by our observance do we force one single result to show up. These thoughts led to such things as multi-world universes where upon each decision that must be made, causes an infinite number of parallel universes to spring up in order to allow all cases to be true, yet only one result to show in each separate universe.
Yes I know, this is getting rather deep indeed and I’ll stop there. You can purchase a few books if you’d like to read up on this further. However, I wanted to end this entry with another plausible solution to the results seen during these tests. One that not many people will except because they’ve long ruled out the existence of a specific property that I think must exist for anything to work. Something they say is not required and can’t be seen. This something, is called the Aether. Its something that scientist of old always thought existed. It’s like the water that carries our waves across the ocean. After all, water is not a wave; it’s just the medium in which the wave travels. So it made logical sense to them that this must be true.
However, no one could ever detect the existence of the Aether and Einstein came along with his Theory of Relativity and all but put a nail in its coffin. He declared that you didn’t need the Aether for things to exist, but he always left room for something existing. He just didn’t know what.
One more small point before I give my explanation. Quantum Physics is not an exact science. It in fact is a system of mathematical equations that form predictions of where particles will appear based on a complex stream of input. But over the years, it has again and again proved correct in its assumptions so everyone lends more and more magical qualities to its facets. The most interesting quality of Quantum Physics functions however is just what they are… They are what are referred to as “Wave Functions”!!!
In all definitions of a wave, it’s an energy force that travels through some medium, yet scientists were now telling us a medium isn’t necessary. That light and electrons travel through nothingness! Think of a wave in water. If there is nothing going on with the water, such as it sitting in a glass, it just sits there, nothing happens. But if you splash your finger into the glass, you see a wave. The wave is a result of the energy traveling through the water that you added with your finger.
So, if we were to add the properties of the Aether back into existence and then push a light particle along its surface, we would be making a wave much like the wave of the ocean, or our glass of water. It’s only a single finger in our glass and it’s only a single particle in our experiment. But the wave exists nonetheless. So as the light particle moves towards the slits, it travels within the wave it is creating as it moves. The wave hits the slits and then separates, carrying the particle to the back screen, canceling out in areas and enforcing in others just like a water wave would behave. Yet, we have only a single particle, not billions of the same particles existing in all realms at once.
So now we have offered another example of the problem without going mystic. So what about the looking part of the problem. After all, when we looked at the particles they changed their behavior. I think this is plausible as well. To explain, lets think about our water again. If I were to create a wave that moved through two slits, and in those slits I setup screens to filter the water though, would I not essentially be canceling out the wave itself? I would smooth out my original waves so that on the backside of the slits they would not longer be waves.
To help think about this, you have to think about what it is to look at something. In order for us to see anything, including detecting light particles, we have to look. But what can we look with? Well, with light of course. But wait! if we look with light particles, that means that we are shooting our light particle with other light particles, would this not effect our original particle in some major way? As another example, imagine having a large boat floating across the ocean making waves and we are much larger in size. We can’t see the waves, nor the boat, but we know they are there from experiments. But we want to see what is going on, so because we are so massive compared to our boats, we fire other boats of equal size at our single boat in order to determine where it is at any particular moment in time. So looking at something is not quite as simple as just looking! But then this opens up a whole different topic indeed, so lets just stick to the subject at hand.
As you can see, applying Occum’s Razor to the topic might yield a little better explanation of what we see (or don’t see), and allow us to provide a better explanation of the expected results without going mystic. Is this the answer? I don’t know, but I suspect its a lot closer than having billions of universes popping into existence every second of our lives!
–glenn hancock