The Science Classroom

Caution: this may be the most random, crazy post so far. Continue at your own risk. Don’t say I didn’t warn you.

Do you know anything about quantum mechanics? Well, that’s good, because I don’t really either. I once heard a quote by Richard Feynman: “If you think you understand quantum mechanics, you don’t understand quantum mechanics” (insert dramatic pause for effect, followed by laughter).  Actually, I know some of the basics of quantum mechanics, but being able to recite something, is a far cry from actually understanding it.

In quantum mechanics, there is an interpretation of the mathematical formulas, which seems to indicate that the observer of anything, affects the object. You can do a little research on Schrödinger’s cat to get a little better understanding. Basically, the way his thought experiment worked, the only way to observe whether the cat is alive or dead, would kill the cat. Now I’ve been thinking about this for a couple of years now and I am just beginning to be able to wrap my brain around it (albeit not very tightly). So if you don’t get it on the first go around, don’t sweat it. Keep thinking about it. If you don’t accept this basic tenet of quantum mechanics, stop reading now, because what follows is based on your acceptance of a theory which has some experimental evidence. To understand that evidence, you’ll need to have a basic understanding of Young’s double-slit experiment.

I know! What’s the point? Right? Actually, I do have one and it goes something like this: if observing the Universe changes the condition of the Universe, how in the world do we know the condition of anything? Most of this thought applies to quantum mechanics, but we could also apply it to, say, a classroom. How many teachers have asked a principal to come observe a particularly rowdy class, only to find when the principal enters the classroom, the students act in a completely different manner? Okay, I know its a stretch, but that’s why they are called analogies.

I’m asking these questions, not because I want you to do some thinking, although that is part of my purpose. I’m asking these questions because I really want to know some answers.  I’m not sure what the answer to the question is. The problem with even asking the questions is that humanity is intrinsically connected to the very thing which they are trying to understand. Its kind of like walking by a mirror and thinking, “That’s not really what I look like! Is it?” Based on Snell’s, you are seeing an exact representation of yourself being reflected back from the mirror. For many of us, we have picture in our heads of what we look like. This is our reality, but once we actually observe our reality, we change it. (I can almost hear the crickets from my vantage point.)

As usual, I always understand things better after I process them through writing. Even though I didn’t talk specifically about quantum entanglement, I think I understand it better than I used to.

Any thoughts? As always, thanks for reading.

This post is from my Summer Research summary which can be found here. Its long and probably a bit boring to many of you, but if you are interested in how I’ve been spending my time, check it out. I am only publishing this because I am proud of the analogy about “Where’s Waldo” and wanted to share that with a broader audience. I had to post all of it, because the analogy alone wouldn’t make any sense without some background.

Any time I hear this phrase (Signal to Noise Ratio), I always think of the guy who once came to my house to work on my cable service. He told me they can sit in their truck and measure the amount of background noise that is leaking from bad connections or improperly insulated wires. They even once told me the signal was turned up/amplified too much which was causing my On Demand problems. (it generally wouldn’t work and kept giving some sort of error code)

In particle physics, when you talk about signal to noise, you are not too far away from this same idea. During particle collisions, there are processes that occur in which we are not really interested. This is called background. That doesn’t mean its not important, it simply means for the particular process at which you are looking, its just not something you want to observe. You would like for your detector to measure this background so that you can then calculate a value for it and subtract it from the actual signal. If you tune out all of the background, you won’t get an accurate depiction of the event in which you are interested. The signal is a value which is predicted (theoretically) by the Standard Model and can be verified (with a particle accelerator) experimentally. If you know the value of your signal, and by know I mean verify a theoretical prediction experimentally, you can then go on to look for new physics above and beyond the energy level at which you are working.

While driving from Oklahoma City to Stillwater, I had an epiphany on how to explain the concept of “signal to noise ratio”. Think about the popular children’s books and games called “Where’s Waldo?” Remember those? (try it by double clicking the picture to find Waldo) You stare at a picture looking for a goofy-faced kid who is wearing a red and white striped sweater with a similarly-colored knit cap. You look and look and look until finally he pops out of the background, plainly obvious and you wonder “why didn’t I seem him sooner?” The key is the red and white striped sweater. If not for that, it would be nearly impossible for you to see Waldo. He would blend into the background.This is especially true as you advance to harder and harder levels of the game. There are more and more people in the picture, therefore Waldo is harder and harder to spot.

Studying the Z boson, as we are, is the “putting on of the sweater”. We are painting a better picture of what the signal, the actual Z boson looks like. When we advance to the next level of the game, i.e. searching for the Higgs, we will have a better understanding of what the background looks like so scientists may then look at whats left and determine whether there is evidence for the Higgs or not. If not, the Standard Model will have to be revised.

Let me know what you think and as usual, thanks for reading.

jb