Wish I had time to post on physics or science recently, but life has been in the way. Here is my little girl on her first day in the world. As a proud new father, forgive me for wanting to trumpet it to the moon.

# Author Archives: foolish physicist

## Disagreeing with “Our Mathematical Universe”

My wife and I have been listening to Max Tegmark’s book “Our Mathematical Universe: My Quest for the Ultimate Nature of Reality” as an audiobook during our trips to and from work lately. When he hit his chapter explaining Quantum Mechanics and his “Level 3 multiverse” I found that I profoundly disagree with this guy. […]

## Flat Earth “Research”

You no doubt heard about this fellow in the last week with the steampunk rocket with “Flat Earth Research” written on the side. In my opinion, he was pretty clearly trolling the media; not much likelihood of resolving any issues about the shape of the Earth if the peak altitude of your rocket is only […]

## E=mc^2

Derived in ten minutes while I was on the toilet: Edit: 11-16-16 There was a slight error in the set-up of the center of mass calculation. Light appears to move an effective mass from -L/2 to L/2-l, the starting and stopping points of light. Here’s the reformulation to capture that. Time spent on this derivation: […]

## Interaction Picture

It’s not always about the cat. Here, I will show how to hop from the time dependent Schrodinger equation to the Interaction picture form. This post is intended to help recover a tiny fraction of the since-destroyed post I originally entitled “NMR and Spin Flipping part II.” I have every intention to reconstruct that post […]

## Magnets, how do they work? (part 2)

(Previous post: Part 1: Magnetic field) I will talk about the origin of the magnetic dipole construct here. Consider a loop of wire… You may have noticed that I posted an entry entitled “NMR and Spin flipping (part 2)” which has since disappeared. It turns out that wordpress doesn’t synch so well between its mobile […]

## Chemical Orbitals from Eigenstates

(Edit 5-12-20: There’s a post-script here regarding a regret about my chosen title) A small puzzle I recently set for myself was finding out how the hydrogenic orbital eigenstates give rise to the S- P- D- and F- orbitals in chemistry (and where s, p, d and f came from). The reason this puzzle is […]

## Powerball Probabilities

If you’ve read anything else in this blog, you’ll know I write frequently about my playing around with Quantum Mechanics. As a digression away from a natural system that is all about probabilities, an interesting little toy problem I decided to tackle is figuring out how the “win” probabilities are determined in the lottery game […]

## Parity symmetry in Quantum Mechanics

I haven’t written about my problem play for a while. Since last I wrote about rotational problems, I’ve gone through the entire Sakurai chapter 4, which is an introduction to symmetry. At the moment, I’m reading Chapter 5 while still thinking about some of the last few problems in Chapter 4. I admit that I […]

## Magnets, how do they work? (part 1)

Subtitle: Basic derivation of Ampere’s Law from the Biot-Savart equation. Know your meme. It’s been a while since this became a thing, but I think it’s actually a really good question. Truly, the original meme exploded from an unlikely source who wanted to relish in appreciating those things that seem magical without really appreciating how […]