React error Updated +Created
RISC-V International Updated +Created
eGroups Updated +Created
Company co-founded by Scott Hassan, early Google programmer at Stanford University, and Carl Victor Page, Jr., Larry Page's older brother.
They were an email list management website, and became Yahoo! Groups after the acquisition.
The company was sold to Yahoo! in August 2000 for $432m and became Yahoo! Groups. They managed to miraculously dodge the Dot-com bubble, which mostly poppet in 2021. After the acquisition, Yahoo started to redirect them to: groups.yahoo.com as can be seen on the Wayback Machine: web.archive.org/web/20000401000000*/egroups.com The first archive of groups.yahoo.com is from February 2001: web.archive.org/web/20010202055100/http://groups.yahoo.com/ and it unsurprisingly looks basically exactly like eGroups.
Michael Moritz Updated +Created
Video 1.
Michael Moritz interview by Stanford Graduate School of Business (2019)
Source. The dude is quirky.
Spontaneous parametric down-conversion Updated +Created
Phenomena that produces photons in pairs as it passes through a certain type of crystal.
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.
Video 1.
One Photon In, TWO Photons Out by JQInews (2010)
Source.
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.
Video 2.
How do you produce a single photon? by Physics World (2015)
Source.
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.
Representations of Updated +Created
Speed of light experiment Updated +Created
Bibliography:
Video 1.
Replicating the Fizeau Apparatus by AlphaPhoenix (2018)
Source. Modern reconstruction with a laser and digital camera.
Video 2.
Visualizing video at the speed of light - one trillion frames per second by MIT (2011)
Source. Fast cameras. OK, this takes it to the next level.
SQL keyword Updated +Created
SymPy special function Updated +Created
shakacode/react_on_rails Updated +Created
Uses Redux, while reactjs/react-rails appears to do that more manually
Live instance: www.reactrails.com/ with source at: github.com/shakacode/react-webpack-rails-tutorial Not the most advanced web-app (a gothinkster/realworld-level would be ideal). Also has clear dependency description, which is nice.
Oh, and the guy behind that project lives in Hawaii (Ciro Santilli's ideal city to live in), has an Asian-mixed son, and two Kinesis Advantage 2 keyboards as seen at twitter.com/railsonmaui/status/1377515748910755851, Ciro Santilli was jealous of him.
SARS-CoV-2 structural protein Updated +Created
Schrödinger equation solution for the hydrogen molecule Updated +Created
Can we make any ab initio predictions about it all?
Video 1.
Quantum Chemistry 10.1 - Hydrogen Molecule Hamiltonian by TMP Chem (2016)
Source. Continued in the following videos, uses the Born–Oppenheimer approximation. Does not give predictions vs experiment?
Chemical bond Updated +Created
Model of the solar system Updated +Created
Planet in the Solar System Updated +Created
Flash memory Updated +Created
Video 1.
The Engineering Puzzle of Storing Trillions of Bits in your Smartphone / SSD using Quantum Mechanics by Branch Education (2020)
Source. Nice animations show how quantum tunnelling is used to set bits in flash memory.
Faster-than-light Updated +Created
In special relativity, it is impossible to travel faster than light.
One argument of why, is that if you could travel faster than light, then you could send a message to a point in Spacetime that is spacelike-separated from the present. But then since the target is spacelike separated, there exists a inertial frame of reference in which that event happens before the present, which would be hard to make sense of.
Even worse, it would be possible to travel back in time:
@cirosantilli/_file/python/python/sphinx Updated +Created
To run each example and see the output run:
./build.sh
xdg-open out/index.html
@cirosantilli/_file/python/sphinx/python/sphinx/class Updated +Created
Basic class example.

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