A Whole New World

Today I got to start on the part of the physics textbook that deals with the somewhat-misleadingly-named modern physics (dating back about a hundred years now!). Excitingly enough this is also the last section of the textbook. The end is drawing near for Tipler and Mosca! So today I read two chapters, Wave-Particle Duality and Quantum Physics and Applications of the Schrödinger Equation, and these were an introduction to quantum physics. They’re actually a pretty well-written introduction, explaining Schrödinger’s equation and wave-particle duality and probability densities in a matter-of-fact way that makes it sound like, okay that makes sense, and not like that is Totally Fucking Weird, which probably should be the default reaction to quantum physics. It covered some of the stuff that had previously been mentioned in the light chapters, and it was a good recap plus adding Schrödinger and some of the quantum things that arise that are classically forbidden like tunneling and partial reflection.

Math-wise, I worked on integrals today. It was actually a pretty easy chapter—I did the whole thing in one go—on multiple integrals. Basically integrating over areas and volumes. The trickiest part here is defining the limits of your integrals, and there was a fun section on change of variables which didn’t make a whole lot of sense because it was said to just use the determinant of the matrix, and if you don’t know what that is we’ll cover that in two chapters. I don’t really remember anything about matrices so that was not quite so helpful for me, but other than that I do feel like I have a good handle on the material in this chapter. I was pretty comfortable working through the problems, although I got a little bogged down in some of the actual calculations. But that’s just me being out of practice and doing stupid things like dropping random x’s when I was doing multi-line integrals.

Really, it was a good day. I feel happy with where I’m at, and I am looking forward to the rest of this week. It’s a little bit of a short week because I’m going to Chicago on Friday, both to go to my cousin’s wedding and to look at houses for when I move to Chicago in just a couple months now! I’m looking forward to that, and I’m a little nervous and hoping that all the places I see don’t suck and that I can find something I can afford. I’m also excited to show my boyfriend Hyde Park so he can get a feel for where I’m going to be living—and for me to get a better feel it because I’ve only been there once!

Today’s fun “new” fact: While I remembered the Pauli exclusion principle, I forgot that it can be seen in the construction of anti-symmetric wave functions, where if both quantum numbers are the same, the wave function will go to zero and so therefore, while it is still a valid solution mathematically, it is rejected as a wave function because it cannot be normalized. It’s a simple way of thinking about a complicated assertion.