Self Interference Patterns

Once I was walking down the street, and I bumped into this guy with this big, purple hat. It was kind of a fedora, but not quite. It was a very nice looking purple hat on an otherwise unremarkable wardrobe. The interesting thing about it was how it reflected the light. If you looked at it from different angles, it appeared to sift between purple and a kind of green. When I asked him where he got the hat, I was surprised at his answer.

I had a shirt like that once. I bought it with one of those professional shoppers they have in department stores, for guys like me that couldn’t match colors to save their lives. I had this shirt that was purple, but had this kind of sheen to it that made it look different colors depending on how you looked at it. The great part was that the tie she picked out matched the color regardless of which direction you looked at the shirt. Needless to say, I always wore that tie with that shirt. For my current job I don’t need to wear a tie (thank goodness) so I’m sure what happened to that odd combination. I’ll never forget how that shirt helped me to make a very large sale, earning me a very large commission.

I was reading this interesting essay about the mysteries of physics the other day. I was talking about light, and all of its strange behaviors. To make the essay accessible to people without PhD’s in advanced optics, it was written in a very clear to understand form. It was talking about light waves and light particles as if they had a conscious mind of their own. Like when beam of light enters into a translucent material like glass, water, it will “bend” to match the particular density of the material. The question is how does the light know which angle to bend? As much they can tell, it bends automatically when it enters into the material, as if it has some previously learned information about the material. I don’t know about you, but I don’t usually know which way I walk into a room until I get inside and look around for a little bit.

Another strange thing about light is how it refracts with itself. If you send light through two different pinpoint holes, it will refract with itself. That is the light waves coming out of one hole with eventually meet up with the light waves coming out of another hole. And they behave just like waves of water do. When two peaks meet, they reinforce each other. When two troughs meet, they also reinforce each other. But when a peak meets a trough, they cancel each other out.

So for one hole, you’d have a bunch of concentric circles emanating out. But when you get two holes, the two circles form a specific pattern. And when they put some film on the far side, the pattern emerges when the interfering light crashes up against the film. There are lines where the peaks meet up, and where the troughs meet up, but when a trough meets a peek, there is nothing. So you get a bunch of discreet lines against the film.

So far, this is easy to understand. But what happens when they turn down the energy of the light, so that instead of coming through in waves, it comes through in particles? One particle of light will go through one hole, then a second later another particle will go through the other hole. What is the pattern that emerges on the film?

You’d expect that it would be a big blog of hits downstream from each hole. A photon, or light particle, would go through the hole, and then smash into the film in front of the hole. Likewise for the other hole. After a while, you’d expect two big collections of dots in two relatively small areas.

But that isn’t what happens. Each photon, as is goes through the hole, immediately changes course and hits a specific point on the screen. When they let the experiment run long enough, they eventually make the exact same pattern that the waves made. A bunch of discreet lines.

So how does each particular photon know where to go when it goes through the whole? It’s like it can look into the future and see what would happen if it were a high energy wave, and go there. It’s like it interacts with it’s future self to figure out where to go.

I took a seminar in goal setting once, and that’s one method that the teacher suggested. Imagine yourself in the future, having achieved all the goals you want to achieve in life. Then just sit down and have a conversation with your future self to figure out how you got there. The only rule is that you have to have got to where you will be only by doing things on your own. Like you can’t win the lotto, or be discovered by a movie producer. You’ve got get in on your own steam. I don’t know if you are into setting goals or anything, but that seemed to be a pretty interesting way to look at things. You can also talk to your future self whenever you run into troubles, and ask yourself advice. Since they’ve already accomplished what you are about to accomplish, they should know what they are talking about.

Light interference patterns have always been an interest of mine. It has been said that Einstein came up with most of his theories by imaging really bizarre and abstract interactions with himself and a beam of light. When you get down to it, light is a really strange and cool thing.

So I was wearing my shirt, and this guy came into the car dealership where I worked. Maybe I was feeling good, because it was the first time I’d worn that shirt/tie combination and had received a bunch of compliments, but the shirt somehow made the guy feel comfortable asking me a bunch of questions about this car he wanted to buy, and eventually bought, making me nice commission.

And the guy wearing the purple hat said he bought it at the goodwill store downtown, for a dollar. He was surprised that nobody else had snatched it up. We got to talking about how you can really find some good stuff all around you if you only keep your eyes peeled and your mind open.