Example: nodejs/sequelize/raw/tree.js
- Implementation agnostic
- Postgres
- stackoverflow.com/questions/67848017/simple-recursive-sql-query
- stackoverflow.com/questions/28688264/how-to-traverse-a-hierarchical-tree-structure-structure-backwards-using-recursiv
- stackoverflow.com/questions/51822070/how-can-postgres-represent-a-tree-of-row-ids
- depth first
- uspecified depth first variant
- preorder DFS
- breadth-first stackoverflow.com/questions/3709292/select-rows-from-table-using-tree-order
- MySQL
- Microsoft SQL Server
Theorized for the graviton.
You can then detect one of the photons, and when you do you know that the other one is there as well and ready to be used. two photon interference experiment comes to mind, which is the basis of photonic quantum computer, where you need two photons to be produced at the exact same time to produce quantum entanglement.
Features Alan Migdall of the National Institute of Standards and Technology. Produced by the Joint Quantum Institute (JQI).
Mentions that this phenomena is useful to determine the efficiency of a single photon detector, as you have the second photon of the pair as a control.
Also briefly describes how the input energy and momentum must balance out the output energy and momentum of the two photons coming out (determined by the output frequency and angle).
Shows the crystal close up of the crystal branded "Cleveland Crystals Inc.". Mentions that only one in a billion photon gets scattered.
Also shows a photomultiplier tube.
Then shows their actual optical table setup, with two tunnels of adjustable angle to get photons with different properties.
Very short whiteboard video by Peter Mosley from the University of Bath, but it's worth it for newbs. Basically describes spontaneous parametric down-conversion.
One interesting thing he mentions is that you could get single photons by making your sunglasses thicker and thicker to reduce how many photons pass, but one big downside problem is that then you don't know when the photon is going to come through, that becomes essentially random, and then you can't use this technique if you need two photons at the same time, which is often the case, see also: two photon interference experiment.
Time-independent Schrödinger equation for a free one dimensional particle by 
Ciro Santilli 37 Updated 2025-07-16
Ciro Santilli 37 Updated 2025-07-16so the solution is:We notice that the solution has continuous spectrum, since any value of can provide a solution.
Show up in the solution of the quantum harmonic oscillator after separation of variables leading into the time-independent Schrödinger equation, much like solving partial differential equations with the Fourier series.
I.e.: they are both:
- solutions to the time-independent Schrödinger equation for the quantum harmonic oscillator
- a complete basis of that space
David Tong's 2009 Quantum Field Theory lectures at the Perimeter Institute by Ciro Santilli 37 Updated 2025-07-16
Ciro Santilli 37 Updated 2025-07-16Lecture notes: Quantum Field Theory lecture notes by David Tong (2007).
By David Tong.
No-Nonsense Quantum Field Theory by Jakob Schwichtenberg (2020) by Ciro Santilli 37 Updated 2025-07-16
Ciro Santilli 37 Updated 2025-07-16This book really tries to recall basic things to ensure that the reader will be able to understand the more advanced ones.
But Ciro Santilli really prefers it when authors error on the side of obvious.
An Introduction To Quantum Field Theory by Peskin and Schroeder (1995) by Ciro Santilli 37 Updated 2025-07-16
Ciro Santilli 37 Updated 2025-07-16Unfortunately, this approach bores Ciro Santilli to death. Or perhaps is too just advanced for him to appreciate. Either of those.
800+ pages.
Unlisted articles are being shown, click here to show only listed articles.