Archive of posts in 2023
The duality between two plane trajectories related by a conformal map
The conformal map transforms the trajectory with energy in potential into the trajectory with energy in potential . I will prove this beautiful result and show some implications of it.
- Categories: physics
- Tags: complex, classical mechanics, canonical transformation, kepler problem, mathematical physics, vector analysis, long paper
Embed the latest Mastodon post in my website
I show the latest Mastodon post in my website hosted on GitHub Pages, and it does not require JavaScript on the client side. How do I do that?
- Categories: update
- Tags: web, jekyll, selfhosting
Rotational symmetry of plane lattices as a simple example of algebraic number theory
For a plane lattice, there is only a finite number of different rotational symmetries that are compatible with the discrete translational symmetry. For example, the 5-fold rotational symmetry is not one of them. Why is that? It turns out that whether an -fold symmetry is compatible with translational symmetry is the same as whether .
- Categories: math
- Tags: complex, condensed matter physics, algebraic number theory, lattice, mathematical physics
I restructured my blog
If you have not noticed, the equations on my blog are now rendered server-side. This change makes it possible for those who turn off JavaScript on their browsers to see the equations. I also updated the theme from Minima v2 to Minima v3.
An 🎃 easy 👻 but 🍬 spooky 💀 Ruby challenge
“It’s the weekend and you’ve just completed a seance with friends. After communing with the dead, you realize a mysterious message was left behind.” What is the decoded message? Use your Ruby skills to find out!
- Categories: programming
- Tags: ruby, code golf, fooling around
You can replace with in the Schrödinger equation?
When someone asks you why it is here instead of or the other way around, you can say that this is just a convention. My professor of quantum mechanics once asked the class similar a question, and I replied with this letter.
- Categories: physics
- Tags: quantum mechanics, letter, complex
How to self-host Overleaf (ShareLaTeX)
It has been a pain setting up Overleaf on my own server. I have finally figured it out and I am sharing my notes here.
- Categories: guide
- Tags: linux, selfhosting, tex
My old computers and my experience of daily driving Linux and self-hosting
I have been using Linux and self-hosting for over a year now. Overall, I would like to say that it is rather satisfactory and that I will continue to use Linux as my daily driver in future. Thinking of that, I felt a little bit nostalgic about my old computers. So I decided to write an article about my old computers and my experience of daily driving Linux now.
- Categories: misc
- Tags: linux, selfhosting
I created Sunniesnow, a rhythm game similar to Lyrica
In order to build a better player community for the rhythm game Lyrica, I created a new rhythm game called Sunniesnow. Learn more about Sunniesnow by joining our Discord server.
- Categories: update
- Tags: update, rhythm game, web
The distribution when indistinguishable balls are put into boxes
Suppose there are distinguishable boxes and indistinguishable balls. Now, we randomly put the balls into the boxes. For each of the boxes, what is the probability that it contains balls? This is a simple combanitorics problem that can be solved by the stars and bars method. It turns out that in the limit with fixed, the distribution tends to be a geometric distribution.
- Categories: math
- Tags: probability, combinatorics, ruby