# Welcome to *otherworldlines*
\[**Announcement on 26 Aug 2023**: I am currently transitioning to a new way of organising literature notes, so you may see a mixture of referencing styles right now. They should be slowly resolved and become consistent in the next few months.\]
## About this site
The current page is the main gate to the site. You can always come back here by clicking "About" on the navigation pane on the left. A list of my research items can be found at [[List]]. The most useful folder is probably the "Topics" folder, so one way to start is to expand this folder in the navigator pane on the left and start browsing. A more fun way to start would be to click on the "Global Graph" icon of the "Interactive Graph" plane on the top-right corner of this site.
In addition to providing information about my research and sharing notes, this site is designed to demonstrate a note-taking system. More about this below.
## About the author
My name is [Diandian Wang](http://web.physics.ucsb.edu/~diandian/), and I am a postdoc at Harvard working in the field of high energy physics. Prior to this, I was a graduate student at UCSB. See my [[CV]] for more details.
I am interested in quantum gravity and tools to study it. One such powerful tool is the [[0123 AdS-CFT dictionary|AdS/CFT]] duality, where a gravitational theory in asymptotically anti-de Sitter spacetime (AdS) is believed to be equivalent to a [[0481 Conformal field theory|conformal field theory]] (CFT) in one lower dimension. I am interested in various aspects of this duality including but not restricted to [[0145 Generalised area|entanglement entropy]], [[0191 Quantum chaos|quantum chaos]] and [[0091 Boundary causality|causality]]. I am also interested in topics of classical gravity (both in AdS and flat space) such as [[0455 Black hole uniqueness theorems|black hole uniqueness]], [[0476 Penrose inequality|the Penrose inequality]], and [[0116 Positive energy theorem|positive energy theorems]]. Moreover, I am interested in [[0147 Celestial holography|celestial holography]], a duality between scattering amplitudes in four-dimensional flat space and a two-dimensional theory on the so-called [[0022 Celestial sphere|celestial sphere]]. You can find out more about my research interests [[List|here]].
You can reach me at [email protected]
. I really appreciate it when people point out typos and mistakes on this site. I also welcome questions, discussions and suggestions.
## Quick links
- [Personal website](https://diandianwang.org/)
- [[CV|My CV]]
- [[List|List of Publications]]
## How to use the site
To navigate the site, you can do one of the following:
1. use the search box;
2. click on any internal link to go to another note;
3. click on any link at the bottom of each page to go to any note that mentions the current note;
4. use the interactive graph to see all notes connected to the current one;
5. look at the global graph;
6. browse the list of topics on the left.
## Who will benefit from these notes
Since most notes are meant to be introductory, it will probably be most useful to beginning graduate students in the field (of holography). However, the connections between the concepts are meant to be helpful to anyone who wants a more bird's-eye view of the subject.
That being said, the person who benefits the most from these notes is, of course, me. Even though it looks like a mini Wikipedia, the biology is entirely different to me: every time I read a note, I know I wrote it, and it is meant to stimulate and bring back the memory already hidden somewhere in my brain instead of creating a new one. Think of it as a good symbiotic mechanism -- it facilitates a human function, not replacing one. But we all know that already: one man's treasure is another man's trash.
Therefore, think of this site as a demo for creating a note-taking system. I have personally devoted time and effort to build a workflow that maximises my work efficiency, and I wish that anyone who shares a similar goal might find this demo instructional.
## What to expect
Expect lots of brief notes that help you make connections between concepts, but do not expect detailed and rigorous discussions; expect useful references but do not expect them to be exhaustive; expect mistakes, typos and broken links.
Broken links (light coloured) are completely normal and will always be there: their contents will be added over time, but more broken links always appear when new content is added. In fact, most literature links (links to notes dedicated to specific papers) will be broken. That is because I don't intend to create them unless it has been mentioned several times. Sometimes I put a link to the url next to the literature link (shown as a little arrow), such as [[Penrose1969]](https://inspirehep.net/literature/54979), which you can click on to find the source of the paper even if the note corresponding to that paper does not exist yet.
## Philosophy behind writing these notes
Many like to emphasise the importance of "thinking outside of the box", but I would say there is much value in "thinking inside the box" - if the box is big and organised. The [Zettlekasten](https://en.wikipedia.org/wiki/Zettelkasten) is such a box ("Kasten" means "box" in German) and it collects notes in a systematic way. I started taking notes this way after reading the book *How to Take Smart Notes* by S. Ahrens. It puts weight on the connections between concepts, and each time you review one page, it reminds you of related topics.
An obvious but important fact about our memory is that we always forget. Instead of improving one's memory, a much simpler boost to our work efficiency is to collect our memory inside a Zettlekasten. Then it only takes a few minutes to recall the things we have forgotten, rather than having to learn them all over again. Of course, one could also try to improve one's memory skills, but that will be a story for another time.
The site is created using [Obsidian](https://obsidian.md/), one of many Zettlekasten-style note-taking apps freely available on the Internet. These notes being public may also help people who are exploring such tools (by serving as a demo), and I am always ready to talk to anyone about ideas for improving and perfecting the workflow.