History of quantum mechanics Updated 2025-07-16
The discovery of the photon was one of the major initiators of quantum mechanics.
Light was very well known to be a wave through diffraction experiments. So how could it also be a particle???
This process "started" in 1900 with Planck's law which was based on discrete energy packets being exchanged as exposed at On the Theory of the Energy Distribution Law of the Normal Spectrum by Max Planck (1900).
This ideas was reinforced by Einstein's explanation of the photoelectric effect in 1905 in terms of photon.
In the next big development was the Bohr model in 1913, which supposed non-classical physics new quantization rules for the electron which explained the hydrogen emission spectrum. The quantization rule used made use of the Planck constant, and so served an initial link between the emerging quantized nature of light, and that of the electron.
The final phase started in 1923, when Louis de Broglie proposed that in analogy to photons, electrons might also be waves, a statement made more precise through the de Broglie relations.
This event opened the floodgates, and soon matrix mechanics was published in quantum mechanical re-interpretation of kinematic and mechanical relations by Heisenberg (1925), as the first coherent formulation of quantum mechanics.
It was followed by the Schrödinger equation in 1926, which proposed an equivalent partial differential equation formulation to matrix mechanics, a mathematical formulation that was more familiar to physicists than the matrix ideas of Heisenberg.
Inward Bound by Abraham Pais (1988) summarizes his views of the main developments of the subjectit:
- Planck's on the discovery of the quantum theory (1900);
- Einstein's on the light-quantum (1905);
- Bohr's on the hydrogen atom (1913);
- Bose's on what came to be called quantum statistics (1924);
- Heisenberg's on what came to be known as matrix mechanics (1925);
- and Schroedinger's on wave mechanics (1926).
Bibliography:
History of special relativity Updated 2025-07-16
Bibliography:
- Subtle is the Lord by Abraham Pais (1982) chapter III "Relativity, the special theory" has a good sketch as you may imagine.
History of the United States Updated 2025-07-16
History of the University of Oxford Updated 2025-07-16
This book series appears to be the one: global.oup.com/academic/content/series/h/history-of-the-university-of-oxford-huo/. A mere 250 pounds+ each.
- youtu.be/uol4V1Wa8B0?t=343 at the University of Bologna, the original system was for students to decide what they would learn, and hire and fire teachers as they decided. This is opposed to the system of the university of Paris, in which teachers make the final decisions. He mentions that this is the system that the University of Oxford and the University of Cambridge use: the "congregation". He mentions that Oxbridge are one of the few universities that maintained this structure (as opposed to having funding sources select the final decision makers)
- youtu.be/uol4V1Wa8B0?t=1327 mentions the quadrangle architecture which served as the basis of the Colleges: make a closed square with everything students need: Chapel, Hall to eat, classes and accommodation. This is based of course on monastic cloisters.
History of Wikipedia Updated 2025-07-16
Hofstadter's law Updated 2025-07-16
As "deadlines" approach, feature sets get cut down, then there are delays, and finally a feasible feature set is delivered some time after the deadline.
The only deadlines that can be met are those of tasks which have already been done but not announced.
This is of course Hofstadter's law.
Home University Library of Modern Knowledge Updated 2025-07-16
Extremelly ironic that it was bought by Oxford University Press and ceased to be "Home University". University is broken.
How can a chemical substance be unstable but not flammable? Updated 2025-07-16
How to report Ubuntu crashes Updated 2025-07-16
Their crash system does not have an amazing user interface.
Tested on Ubuntu 21.10.
After something crashes, look under
/var/crash for a crash file, which helps to determine which package to report under on Launchpad.E.g. a file
/var/crash/_usr_sbin_gdm3.0.crash makes you want to file the bug under gdm at: bugs.launchpad.net/ubuntu/+source/gdm/+filebugThen, while reporting the bug, you want to give the developpers access to that Ubuntu's crash report system has already uploaded the
.crash file. But you can't publicly upload it because it contains memory dumps and could contain secret information. The way to do it is to look at the ID under:sudo cat /var/crash/_usr_sbin_gdm3.0.uploaded.crash for you, so you just have to confirm it and give the ID on the ticket.You can view a list of all your uploaded errors at:and each of those contain a link to:which you yourself cannot see.
xdg-open https://errors.ubuntu.com/user/$(sudo cat /var/lib/whoopsie/whoopsie-id)https://errors.ubuntu.com/oops/<.uloaded error id>askubuntu.com/questions/434431/how-can-i-read-a-crash-file-from-var-crash asks how to read the
.crash files.Running:splits it up into a few files, but does not make any major improvements.
sudo apport-unpack /var/crash/_usr_sbin_gdm3.0.crash /tmp/appapport-retracesudo apt install apport-retrace
sudo chmod 666 /var/crash/_usr_sbin_gdm3.0.crash
apport-retrace -g /var/crash/_usr_sbin_gdm3.0.crashTried:but then
echo "deb http://ddebs.ubuntu.com $(lsb_release -cs) main restricted universe multiverse" | sudo tee -a /etc/apt/sources.list.d/ddebs.list
echo -e "deb http://ddebs.ubuntu.com $(lsb_release -cs)-updates main restricted universe multiverse\ndeb http://ddebs.ubuntu.com $(lsb_release -cs)-proposed main restricted universe multiverse" | sudo tee -a /etc/apt/sources.list.d/ddebs.list
sudo apt install ubuntu-dbgsym-keyringsudo apt update fails with:E: The repository 'http://ddebs.ubuntu.com impish-security Release' does not have a Release file. How to store data in the Bitcoin blockchain Updated 2025-07-16
There are apparently two methods:
- in the script, e.g. as in the Genesis block message
- in output addresses
Specific implementations:
- eternitywall.it/ Eternity WallLaunched 2015 www.newsbtc.com/news/bitcoin/eternity-wall-records-1150-documents-blockchain-first-year/Shutdown sometime after 2019, working archive: web.archive.org/web/20190417074034/https://eternitywall.it/ says "Sorry, the service is not properly working at the moment..." and last working message timestamped "April 16, 2019 8:02 PM GMT".
How to teach and learn physics Updated 2025-07-16
The approach many courses take to physics, specially "modern Physics" is really bad, this is how it should be taught:
- start by describing experiments that the previous best theory did not explain, see also: Section "Physics education needs more focus on understanding experiments and their history"
- then, give the final formula for the next best theory
- then, give all the important final implications of that formula, and how it amazingly describes the experiments. In particular this means: doing physics means calculating a number
- then, give some mathematical intuition on the formulas, and how the main equation could have been derived
- finally, then and only then, start deriving the outcomes of the main formula in detail
This is likely because at some point, experiments get more and more complicated, and so people are tempted to say "this is the truth" instead of "this is why we think this is the truth", which is much harder.
Related:
- settheory.net/learnphysics and www.youtube.com/watch?v=5MKjPYuD60I&list=PLJcTRymdlUQPwx8qU4ln83huPx-6Y3XxH from settheory.net
- math.ucr.edu/home/baez/books.html by John Baez. Mentions:Ciro Santilli is trying to change that: OurBigBook.com.
This webpage doesn't have lots of links to websites. Websites just don't have the sort of in-depth material you need to learn technical subjects like advanced math and physics — at least, not yet. To learn this stuff, you need to read lots of books
- web.archive.org/web/20210324182549/http://jakobschwichtenberg.com/one-thing/ by Jakob Schwichtenberg
How to teach Explain how to make money with the lesson Updated 2025-07-16
People will be more interested if they see how the stuff they are learning is useful.
Achieving novel results for science, or charitable goals (e.g. creating novel tutorials) are also equaly valid. Note that those also imply you being able to make a living out of something, just that you will be getting donations and not become infinitey rich. and that is fine.
Projects don't need of course to reach the level of novel result. But they must at least aim at moving towards that.
This is one of the greatest challenges of education, since a huge part of the useful information is locked under enterprise or military secrecy, or even open academic incomprehensibility, making it nearly to impossible for the front-line educators to actually find and teach real use cases.
How to teach Explain why the subject is beautiful Updated 2025-07-16
And if you really can't make money from a subject, there is only one other thing people crave: beauty.
You have to give the beauty motivations upfront, before boring people to death with endless prerequisites, otherwise no one will ever want to learn it.
Human Compatible Updated 2025-07-16
The key takeaway is that setting an explicit value function to an AGI entity is a good way to destroy the world due to poor AI alignment. We are more likely to not destroy by creating an AI whose goals is to "do want humans what it to do", but in a way that it does not know before hand what it is that humans want, and it has to learn from them. This approach appears to be known as reward modeling.
Some other cool ideas:
- a big thing that is missing for AGI in the 2010's is some kind of more hierarchical representation of the continuous input data of the world, e.g.:
- game theory can be seen as part of artificial intelligence that deals with scenarios where multiple intelligent agents are involved
- probability plays a crucial role in our everyday living, even though we don't think too much about it every explicitly. He gives a very good example of the cost/risk tradeoffs of planning to the airport to catch a plane. E.g.:
- economy, and notably the study of the utility, is intrinsically linked to AI alignment
Human vs computer chess Updated 2025-07-16
Hydrogen line Updated 2025-07-16
Hypercube Updated 2025-07-16
Convex hull of all (Cartesian product power) D-tuples, e.g. in 3D:
( 1, 1, 1)
( 1, 1, -1)
( 1, -1, 1)
( 1, -1, -1)
(-1, 1, 1)
(-1, 1, -1)
(-1, -1, 1)
(-1, -1, -1) Hyperfine structure Updated 2025-07-16
Small splits present in all levels due to interaction between the electron spin and the nuclear spin if it is present, i.e. the nucleus has an even number of nucleons.
As the name suggests, this energy split is very small, since the influence of the nucleus spin on the electron spin is relatively small compared to other fine structure.
The most important examples:
- hydrogen line useful in astronomy, and also the simplest possible case between 1s
- caesium standard, which is used to define the second in the International System of Units since 1967.
HyperPhysics Updated 2025-07-16
Created by Dr. Rod Nave from Georgia State University, where he worked from 1968 after his post-doc in North Wales on molecular spectroscopy.
While there is value to that website, it always feels like it falls a bit too short as too "encyclopedic" and too little "tutorial-like". Most notably, it has very little on the history of physics/experiments.
Ciro Santilli likes this Rod, he really practices some good braindumping, just look at how he documented his life in the pre-social media Internet dark ages: hyperphysics.phy-astr.gsu.edu/Nave-html/nave.html
The website evolved from a HyperCard stack, as suggested by the website name, mentioned at: hyperphysics.phy-astr.gsu.edu/hbase/index.html.
Shame he was too old for CC BY-SA, see "Please respect the Copyright" at hyperphysics.phy-astr.gsu.edu/hbase/index.html.
exhibits.library.gsu.edu/kell/exhibits/show/nave-kell-hall/capturing-a-career has some good photo selection focused on showing the department, and has an interview.
Kell hall is a building of GSU that was demolished in 2019: atlanta.curbed.com/2020/1/31/21115980/gsu-georgia-state-atlanta-kell-hall-demolition-park-library-north
Knol Updated 2025-07-16
Very similar to OurBigBook.com!
People who worked on it:
- Udi Manber: project lead
- www.wired.com/2008/07/google-knol/ mentions various engineers. The original page had photos, including the full team photo, but these died, but are visible on the archive: web.archive.org/web/20151220002650/http://www.wired.com/2008/07/google-knol/.
- Ben McMahan: "Developed, launched, and maintained Knol", mentioned at:
- x.com/benjmcmahan
- www.benjaminmcmahan.com/ has email
ben.j.mcmahan@gmail.com
- Michael McNally (2007-2009), "project's technical lead": mentioned at: www.wired.com/2008/07/google-knol/,
- github.com/xiangtiandai Xiangtian Dai
xiangtian.dai@google.com - Mohsin Ahmed: can't find any online profiles
Replying to a listener phone-in question WNYC radio, mediated by Brian Lehrer.
It was about to launch it seems, and it was not clear at the time that anyone could write content, as opposed to only selected people.
It was about to launch it seems, and it was not clear at the time that anyone could write content, as opposed to only selected people.
Jimmy then corrects that misinformation. He then clearly states that since there can be multiple versions of each article, including opinion pieces, like OurBigBook.com, Knol would be very different to Wikipedia, more like blogging than encyclopedia.
Google Knol: the future of academic journals? by Doug Belshaw (2010)
Source. Bibliography:
- Wikipedia & Knol: Why Knol Already Failed by gwern.net (2009). So there was some kind of monetary payment on the site. Interesting and sad.
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