Knowledge Hub

I greatly enjoyed David Kaiser’s How the Hippies Saved Physics (here’s my review from 2011), so when I ran across a mention of this new book with “Quantum” in the title, I immediately sought out a copy. This sort of thing is highly relevant to my interests. Kaiser is a professor at MIT with a joint appointment in both physics and history of science, and as you would expect this collection of essays splits time between those two fields. The book contains a handful of pieces relating to Kaiser’s work in physics, chiefly about a “cosmological” test of quantum physics, using light from distant quasars as a random number generator for a Bell’s Inequality test (I talked briefly about this idea in the context of football in 2015). There are also a larger number of pieces primarily about the historical and social context of physics, mostly in the mid-to-late 20th century. Almost all of these were previously published (I think there’s only one that doesn’t have a “A version of this previously..

As someone who derives significant income from writing for money, I end up spending a fair bit of time reading writing advice. Not because I'm in need of tips, myself-- after many years of this, I've got a routine that mostly works for me. Rather, I'm looking for good advice to pass on to other people, because I get asked for advice on a regular basis, and I don't really have much of my own to offer. That's how I came to read this advice post from Alyx Dellamonica, making an analogy between figuring out how fiction works and trying to learn about cars from a junkyard. I like the junkyard analogy quite a bit, but along the way she makes a couple of passing mentions to physics that I absolutely hate. Here's the first: With the arts, you not a physics professor laying out a formula, some cut-and-dried procedure for which there is one satisfactory answer. You’re not showing someone how to paint the perfect yellow line down the middle of a strip of road, or fly an ai

Scattering Amplitude  Spinless Particle  we are dealing with quantum description of scattering.  Elastic Scattering $ \rightarrow $ between two spinless, non-relativistic particles of masses m1 and m2. During the scattering process, the particles interact with one another. If the interaction is time independent, we can describe the two-particle system with stationary states.  \begin{equation}\Psi\left(\vec{r}_{1}, \vec{r}_{2}, t\right)=\psi\left(\vec{r}_{1}, \vec{r}_{2}\right) e^{-i E_{T} t / n}\end{equation}  $ E_T $ is total energy.  \begin{equation}\left[-\frac{\hbar^{2}}{2 m_{1}} \vec{\nabla}_{1}^{2}-\frac{\hbar^{2}}{2 m_{2}} \vec{\nabla}_{2}^{2}+\hat{V}\left(\vec{r}_{1}, \vec{r}_{2}\right)\right] \psi\left(\vec{r}_{1}, \vec{r}_{2}\right)=E_{T} \psi\left(\vec{r}_{1}, \vec{r}_{2}\right) \end{equation}     defining $ r= \mid \vec{r_1}- \vec{r_2}\mid \implies V(