In large deviations theory, the Contraction Principle is a fundamental result that provides insights into the asymptotic behavior of probability measures associated with stochastic processes. Large deviations theory focuses on understanding the probabilities of rare events and how these probabilities behave in limit scenarios, particularly when considering independent and identically distributed (i.i.d.) random variables or other stochastic systems.
The Hajek projection, named after the Czech mathematician Jaroslav Hajek, is a concept from the field of statistics, particularly in the context of nonparametric estimation in statistical inference. It refers to a projection operator that is used in the context of estimating a function, usually with respect to a certain kind of norm.
Token reconfiguration refers to the process of modifying the properties, rules, or characteristics of a digital token within a blockchain or cryptocurrency ecosystem. Tokens can represent a variety of assets or utilities, including but not limited to currencies, access rights, or ownership in a particular project or platform.
"Mundus Subterraneus," published in 1665 by the German scholar and theologian Athanasius Kircher, is a notable work that explores the mysteries of the underground world. In this comprehensive text, Kircher delves into various topics such as geology, the nature of the Earth, subterranean water systems, and the existence of subterranean life. He presents a mix of scientific observations and imaginative theories, reflecting the knowledge and beliefs of his time.
Phonurgia Nova is a French sound art organization founded in 1982, known for its innovative approach to sound arts and audio experimentation. The organization focuses on the intersection of sound, music, and technology, promoting research and artistic projects that explore the aesthetic and conceptual dimensions of sound. It serves as a platform for artists, musicians, researchers, and sound designers to collaborate and showcase their work.
Florence van Straten is known for her work as a Dutch actress and television presenter. She has appeared in various television shows and films, gaining recognition in the entertainment industry. Additionally, she may have made contributions to Dutch culture through her performances and public appearances. For the most accurate and up-to-date information, it would be best to check recent sources or news articles.
The growing number of parameters of the Standard Model is one big source of worry for early 21st century physics, much like the growing number of particles was a worry in the beginning of the 20th (but that one was solved by 2020).
A friend of mine who's a rich man - he invented some kind of simple digital switch - tells me about these people who contribute money to make prizes or give lectures: "You always look at them carefully to find out what crookery they're trying to absolve their conscience of."
But do you know what, Cirism is totally fine with taking indulgences to absolve someone from their past sins, so long as they have repented. Everyone deserves a second chance.
Fine structure by Ciro Santilli 40 Updated 2025-07-16
Split in energy levels due to interaction between electron up or down spin and the electron orbitals.
Numerically explained by the Dirac equation when solving it for the hydrogen atom, and it is one of the main triumphs of the theory.
Zeeman effect by Ciro Santilli 40 Updated 2025-07-16
Split in the spectral line when a magnetic field is applied.
Non-anomalous: number of splits matches predictions of the Schrödinger equation about the number of possible states with a given angular momentum. TODO does it make numerical predictions?
www.pas.rochester.edu/~blackman/ast104/zeeman-split.html contains the hello world that everyone should know: 2p splits into 3 energy levels, so you see 3 spectral lines from 1s to 2p rather than just one.
p splits into 3, d into 5, f into 7 and so on, i.e. one for each possible azimuthal quantum number.
It also mentions that polarization effects become visible from this: each line is polarized in a different way. TODO more details as in an experiment to observe this.
Video 1.
Experimental physics - IV: 22 - Zeeman effect by Lehrportal Uni Gottingen (2020)
Source.
This one is decent. Uses a cadmium lamp and an etalon on an optical table. They see a more or less clear 3-split in a circular interference pattern,
They filter out all but the transition of interest.
Video 2. Source. Does not appear to achieve a crystal clear split unfortunately.
Video 1. Source.
Institutional video about the 1974 single electron experiment by Merli, Missiroli, Pozzi from the University of Bologna.
Shows them manually making the biprism by drawing a fine glass wire and coating it with gold.
Then actually show the result live on a television screen, where you see the interference patterns only at higher electron currents, and then on photographic film.
This was elected "the most beautiful experiment" by readers of Physics World in 2002.
Italian title: "Interferenza di elettroni". Goddammit, those Italian cinematographers can make even physics look exciting!

Pinned article: Introduction to the OurBigBook Project

Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
We have two killer features:
  1. topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculus
    Articles of different users are sorted by upvote within each article page. This feature is a bit like:
    • a Wikipedia where each user can have their own version of each article
    • a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
    This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
    Figure 1.
    Screenshot of the "Derivative" topic page
    . View it live at: ourbigbook.com/go/topic/derivative
  2. local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:
    This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
    Figure 2.
    You can publish local OurBigBook lightweight markup files to either https://OurBigBook.com or as a static website
    .
    Figure 3.
    Visual Studio Code extension installation
    .
    Figure 4.
    Visual Studio Code extension tree navigation
    .
    Figure 5.
    Web editor
    . You can also edit articles on the Web editor without installing anything locally.
    Video 3.
    Edit locally and publish demo
    . Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension.
    Video 4.
    OurBigBook Visual Studio Code extension editing and navigation demo
    . Source.
  3. https://raw.githubusercontent.com/ourbigbook/ourbigbook-media/master/feature/x/hilbert-space-arrow.png
  4. Infinitely deep tables of contents:
    Figure 6.
    Dynamic article tree with infinitely deep table of contents
    .
    Descendant pages can also show up as toplevel e.g.: ourbigbook.com/cirosantilli/chordate-subclade
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact