Devil Updated 2025-07-16
Diacritic Updated 2025-07-16
Dialog between Fisherman and Woodcutter Updated 2025-07-16
Lit: fish timber question answer.
The dialog is also known as allegory for an incredibly deep philosophical discussion between an idealized wise woodcutter and a fisherman, e.g. mentioned at: www2.kenyon.edu/Depts/Religion/Fac/Adler/Writings/Fisherman%20and%20Woodcutter.pdf
This song is just too slow for Ciro Santilli to make much out of it.
Bibliography:
Dialog between Fisherman and Woodcutter Chinese traditional painting by Xie Shichen
. Dialog between Fisherman and Woodcutter uploaded by Fei Sun
. Source. Diameter Updated 2025-07-16
Diffraction limit Updated 2025-07-16
Digital currency Updated 2025-07-16
Digital electronics Updated 2025-07-16
Digital micromirror device Updated 2025-07-16
The Insane Engineering of DLP by Zack Freedman (2022)
Source. Digital-to-analog converter Updated 2025-07-16
Dildo Updated 2025-07-16
Dilution refrigerator Updated 2025-07-16
Reaches 2 mK[ref]. youtu.be/upw9nkjawdy?t=487 from Video "Building a quantum computer with superconducting qubits by Daniel Sank (2019)" mentions that 15 mK are widely available.
Used for example in some times of quantum computers, notably superconducting quantum computers. As mentioned at: youtu.be/uPw9nkJAwDY?t=487, in that case we need to go so low to reduce thermal noise.
Dilution refrigerator manufacturer Updated 2025-07-16
Diminutive Updated 2025-07-16
Diode Updated 2025-07-16
Ideally can be thought of as a one-way ticket gate that only lets electrons go in one direction with zero resistance! Real devices do have imperfections however, so there is some resistance.
First they were made out of vacuum tubes, but later semiconductor diodes were invented and became much more widespread.
Diode bridge Updated 2025-07-16
Dipole antenna Updated 2025-07-16
Radio Wave Properties: Electric and Magnetic Dipole Antennae by Harvard Natural Sciences Lecture Demonstrations (2020)
Source. The dude lights bulbs on an antenna made of a single piece of copper, powered with EM radiation. Amazing.Dipole antenna receiver animation
. Source. Dipole antenna transmitter animation
. Source. Divisions of the University of Oxford Updated 2025-07-16
Dirac equation Updated 2025-07-16
Adds special relativity to the Schrödinger equation, and the following conclusions come basically as a direct consequence of this!
Experiments explained:
Experiments not explained: those that quantum electrodynamics explains like:See also: Dirac equation vs quantum electrodynamics.
- Lamb shift
- TODO: quantization of the electromagnetic field as photons?
The Dirac equation is a set of 4 partial differential equations on 4 complex valued wave functions. The full explicit form in Planck units is shown e.g. in Video 1. "Quantum Mechanics 12a - Dirac Equation I by ViaScience (2015)" at youtu.be/OCuaBmAzqek?t=1010:Then as done at physics.stackexchange.com/questions/32422/qm-without-complex-numbers/557600#557600 from why are complex numbers used in the Schrodinger equation?, we could further split those equations up into a system of 8 equations on 8 real-valued functions.
Equation 1.
Expanded Dirac equation in Planck units
. PHYS 485 Lecture 14: The Dirac Equation by Roger Moore (2016)
Source. Dirac equation solution for the hydrogen atom Updated 2025-07-16
Predicts fine structure.
Bibliography:
How To Solve The Dirac Equation For The Hydrogen Atom | Relativistic Quantum Mechanics by Dietterich Labs (2018)
Source. Dirac equation vs quantum electrodynamics Updated 2025-07-16
TODO: in high level terms, why is QED more general than just solving the Dirac equation, and therefore explaining quantum electrodynamics experiments?
Also, is it just a bunch of differential equation (like the Dirac equation itself), or does it have some other more complicated mathematical formulation, as seems to be the case? Why do we need something more complicated than
The main high level insight seems to be that The Dirac equation does not work for more than one electron.
Bibliography:
- physics.stackexchange.com/questions/101307/dirac-equation-in-qft-vs-relativistic-qm
- physics.stackexchange.com/questions/44188/what-is-the-relativistic-particle-in-a-box/44309#44309 says:
- physics.stackexchange.com/questions/64206/why-is-the-dirac-equation-not-used-for-calculations
- www.physicsforums.com/threads/is-diracs-equation-still-useful-after-qed-is-developed.663994/
There are unlisted articles, also show them or only show them.


