## A Knerd-y Tattoo Story: The Schrödinger Equation

A few of the men and women here at Knewton have had the pleasure of seeing me shirtless, and noticed my very nerdy tattoo. A few of them have asked me to explain it, so here goes:

This equation is the Schrödinger Equation. The link to the Wikipedia page is here. If you’re interested, I suggest you check it out. It’s a little mathy, but it also has some great animations, and does a better job of explaining the equation than I could. For those of you who are interested in the math, check it out there or better yet, get a textbook and go learn some physics! I’m going to focus more on what it means to me and why it’s on my back.

First, what it means to everyone: the Schrödinger Equation is one of the fundamental equations of quantum mechanics, and will tell you (among other things) how an electron will behave in the vicinity of an atomic nucleus. It applies to any particle moving at any but the highest of velocities, in all but the highest gravitational fields. Physicists often refer to it as the “wave equation.” We have an equation that works even for high velocity, but it’s much more difficult to work with, and doesn’t look as cool in the form of ink on human skin. As far as the equation that works in high gravitational fields, if you can figure that one out, your award will be a Nobel Prize.

In terms of what the equation means to me, that’s a little more complicated. To explain that, I want to talk about how I was taught physics, and how I ran into this equation at various points in my education.

One thing you should know is that physicists only know how to solve a handful of equations, and this is one of them (being a physicist is mostly about knowing how to apply one of your few solvable equations into every situation where it’ll give you the right answer). The way I took physics as an undergrad at UCSD, we first ran through an overview of physics in a five trimester series (while simultaneously taking general ed requirements). We covered classical mechanics, a little thermodynamics, electrodynamics, optics and special relativity, and finally, at the end of our sophomore year, quantum mechanics. It was in that class I saw the equation for the first time. I had only recently learned the math I needed to solve it, and I still had trouble connecting the math on my paper to the physical situation at hand.

During the last couple of years of college, the physics students take the more advanced physics courses: classical mechanics, electrodynamics, thermodynamics, and quantum mechanics, more or less a year of each. I put myself on a five-year plan, so I took a little bit longer. I also tried taking a graduate Quantum Mechanics class before the undergrad class (with some mixed results), where I worked with the Schrödinger equation again. This time, I felt more familiar with it. I was more practiced, I could solve it in trickier situations. I was getting better.

During this time, an acquaintance of mine showed me a surf board with the Schrödinger Equation on it. Putting the “wave equation” on a board that travels on waves? A pretty nerdy pun. I liked it.

Then, during my first and second years as a graduate student, I again took quantum mechanics more or less continuously, along with the other graduate classes (including classical mechanics, electrodynamics, and thermodynamics). This time I really felt like I understood what we were doing. The math was easy, and the equation was now mine. By this point, I’d spent countless time burning the equation into my soul. I could now apply it to a totally unfamiliar situation and get a valid result. If I had problems solving the equation exactly, I could write a computer program to give me a solid approximate solution. I thought about that surf board with the equation on it, and after awhile, decided I wanted it on my back.

I spent a couple of years talking about it, and then, in the fall of 2006, I got it done. I went to a nearby tattoo parlor, and went through several drafts over the course of a few weeks with the tattoo artist, asking for this part to look a little different, or that part to be a little sleeker. When I liked what I saw, I told him to pull out his needle. It took maybe an hour or two. It is, to date, my only tattoo.

So now I have branded on my body an equation that I had already branded on my soul. At the beach, nerds instantly recognize me as a fellow and come up to strike up a conversation. It’s great.

It does confuse a lot of people, though. Somehow there seems to be this idea out there that tattoos shouldn’t be nerdy, or maybe that they shouldn’t be intellectual. A lot of people ask me, “What if someday they prove the equation wrong?” I usually answer that it’s already only an approximation, and it’s so close to being right that it’s very useful.

So what about you? Anything branded on your soul that is worthy of branding on your body?

*Wondering what a physicist like Will is doing working at Knewton? Stay tuned for his next post! *