Quantum entanglement is often called spooky/surprising/unintuitive, but they key question is to understand why.
To understand that, you have to understand why it is fundamentally impossible for the entangled particle pair be in a predefined state according to experiments done e.g. where one is deterministically yes and the other deterministically down.
In other words, why local hidden-variable theory is not valid.
How to generate entangled particles:
- particle decay, notably pair production
- for photons, notably: spontaneous parametric down-conversion, e.g.: www.youtube.com/watch?v=tn1sEaw1K2k "Shanni Prutchi Construction of an Entangled Photon Source" by HACKADAY (2015). Estimatd price: 5000 USD.
Contains the clearest Bell test experiment description seen so far.
It clearly describes the photon-based 22.5, 45 degree/85%/15% probability photon polarization experiment and its result conceptually.
It does not mention spontaneous parametric down-conversion but that's what they likely hint at.
Done in Collaboration with 3Blue1Brown.
Question asking further clarification on why the 100/85/50 thing is surprising: physics.stackexchange.com/questions/357039/why-is-the-quantum-venn-diagram-paradox-considered-a-paradox/597982#597982
Quantum Mechanics: Animation explaining quantum physics by Physics Videos by Eugene Khutoryansky (2013)
Source. Usual Eugene, good animations, and not too precise explanations :-) youtu.be/iVpXrbZ4bnU?t=922 describes a conceptual spin entangled electron-positron pair production Stern-Gerlach experiment as a Bell test experiments. The 85% is mentioned, but not explained at all.Quantum Entanglement Lab by Scientific American (2013)
Source. The hosts interview Professor Enrique Galvez of Colgate University who shows briefly the optical table setup without great details, and then moves to a whiteboard explanation. Treats the audience as stupid, doesn't say the keywords spontaneous parametric down-conversion and Bell's theorem which they clearly allude to. You can even them showing a two second footage of the professor explaining the rotation experiments and the data for it, but that's all you get. Institute of Electrical and Electronics Engineers by
Ciro Santilli 37 Updated 2025-07-01 +Created 1970-01-01
There are no stable isotopes.
Ridiculous cases of political correctness censorship by
Ciro Santilli 37 Updated 2025-07-01 +Created 1970-01-01
- Stack Exchange's censorship of "I think Trump is disgusting as a person" from Ciro Santilli's profile: cirosantilli.com/china-dictatorship/sstack-overflow-forbids-criticizing-the-character-of-genocidal-political-leaders-like-xi-jinping
Cute simple paper-cut stop motion animations videos by Mithuna Yoganathan, a PhD in theoretical physics at the University of Cambridge: www.damtp.cam.ac.uk/person/my332.
There is value in tutorials written by early pioneers of the field by
Ciro Santilli 37 Updated 2025-07-01 +Created 1970-01-01
Everyone is beginner when the field is new, and there is value in tutorials written by beginners.
For example, Ciro Santilli felt it shocking how direct and satisfying Richard Feynman's scientific vulgarization of quantum electrodynamics were, e.g. at: Richard Feynman Quantum Electrodynamics Lecture at University of Auckland (1979), and that if he had just assumed minimal knowledge of mathematics, he was about to give a full satisfactory picture in just a few hours.
Other supporters of this:
- Ron Maimon: the same also applies to early original papers of the field, not just tutorials
- Dean Kamen: quick mention at: fi.edu/en/awards/laureates/dean-kamen, but a better longer mention on Dreamer (2020), nearby section from trailer: youtu.be/Cj2VKVJKf1I?t=16
Why phosphorus has multiple valencies? by
Ciro Santilli 37 Updated 2025-07-01 +Created 1970-01-01
Partial index partial derivative notation by
Ciro Santilli 37 Updated 2025-07-01 +Created 1970-01-01
This notation is not so common in basic mathematics, but it is so incredibly convenient, especially with Einstein notation as shown at Section "Einstein notation for partial derivatives":
This notation is similar to partial label partial derivative notation, but it uses indices instead of labels such as , , etc.
That's what usually fucks up parallel programs.
The steps are sorted in roughly chronological order. The project might fail at any point, and some steps may be carried in parallel:
- create a basic implementation of the website, without advanced features like PageRank sorting and WYSIWYG. This is not much more than a blog with some extra metadata, so it is definitely achievable with constrained resources.
- Ciro would like to volunteer to work for free for this teacher and students to help the students learn.Ciro would start by mapping the headers of the lecture notes onto the website, and then slowly adding content as he feels the need to improve certain explanations.Finding teachers willing to allow this will be a major roadblock: how to convince teachers to use CC BY-SA.
- once some level of validation as been done, Ciro will start looking for charitable charitable grant opportunities more aggressively
- if things seem to be working, start adding more advance features: PageRank-like ranking sorting and WYSIWYG editingThe recommendation algorithms notably is left for a second stage because it needs real world data to be tested. And at the beginning, before Eternal September kicks in, there would be few posts written by well educated university students, so a simple sort by upvote would likely be good enough.
Ciro decided to start with a decent markup language with a decent implementation: OurBigBook Markup. Once that gets reasonable, he will move on to another attempt at the website itself.
The project description was originally at: github.com/cirosantilli/write-free-science-books-to-get-famous-website but being migrated here. The original working project name was "Write free books to get famous website", until Ciro decided to settle for
OurBigBook.com
and fixed the domain name. Variational formulation of a partial differential equation by
Ciro Santilli 37 Updated 2025-07-01 +Created 1970-01-01
Ciro Santilli finds it interesting that radioactive decay basically kickstarted the domain of nuclear physics by essentially providing a natural particle accelerator from a chunk of radioactive element.
The discovery process was particularly interesting, including Henri Becquerel's luck while observing phosphorescence, and Marie Curie's observation that the uranium ore were more radioactive than pure uranium, and must therefore contain other even more radioactive substances, which lead to the discovery of polonium (half-life 138 days) and radium (half-life 1600 years).
List of Nobel Prizes in Physiology and Medicine by
Ciro Santilli 37 Updated 2025-07-01 +Created 1970-01-01
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