Institutional history of Chicago Pile-1 and its controlled self-sustaining chain-reaction demonstration on 2 December 1942. Used for the experiment’s purpose and qualitative apparatus, not construction specifications.
Physical Review Letters 34, 1472–1474. The inspected primary abstract reports a gravitationally induced neutron-interferometer phase shift. The elementary rectangular-path phase calculation in the concept article is explicitly presented as a model, rather than as a reconstruction of the original apparatus.
Institutional apparatus description. Overview, Fig. 2 and NIOF subsection document perfect-crystal silicon blades with a common base and environmental isolation for phase stability. Accessed 2026-10-31.
Primary research paper. Introduction, printed pp. 2–3, equations (1.1)–(1.2), defines codimension q+1 symmetry generators and q-dimensional charged operators. A one-form symmetry therefore has codimension-two generators.
Authored Cambridge lecture notes. Chapter 3 defines Dp-branes, their transverse positions and the type-II dimensionality distinction; chapter 8 develops compactification and T-duality.
Nature 116, p. 278. The author's response describes simultaneous recoil and photoelectric events, directional correlations, and the consequences for BKS theory.
Science Advances 3, e1602258. Figure 1 and Results and Discussion explain skimmer interference and its experimental suppression by cooling. Preprint: arxiv.org/abs/1607.04844
The Stejskal-Tanner equation relates diffusion-sensitive echo attenuation to a rectangular gradient-pair experiment:
It assumes free Gaussian diffusion with a constant scalar diffusion coefficient , ideal refocusing and two equal nonoverlapping rectangular gradient pulses of magnitude and duration , whose starting times are separated by . The gyromagnetic ratio is angular. The baseline is an otherwise matched echo without the applied diffusion-encoding gradients. These definitions are part of the formula, rather than optional choices of notation.[ref]
The finite-duration term follows directly from the encoding history. Write . The effective encoding rises linearly from zero to , stays constant for , then falls linearly to zero. Each ramp contributes to the diffusion weighting b-value, so
The two physical gradients can have the same polarity: the intervening pulse reverses the effective phase-encoding sign.
Figure 1.
Reused original illustration of a refocused gradient pair and its accumulated encoding
. The chosen illustrative timings are not a reconstruction of a historical run. Both physical gradient pulses have the same sign; refocusing reverses their effective encoding sign. Squaring the lower trace and integrating gives the finite-duration correction. Details.
For the illustrated and , the normalized integral is , rather than . This isolates the pulse-duration correction without assigning an unmeasured gradient amplitude.
The 1965 work combined theory with apparatus tests, including slow self-diffusion in dry glycerol.[ref] Restricted diffusion, flow, background gradients and measurement noise require their own interpretation; fitting a single attenuation to this equation does not establish all of its assumptions.

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 5. . 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.
  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