A monopolistic operating system that only exists in the 2010's because of the IBM-linked historical lock-in and constant useless changes of the Microsoft Word document format to prevent cross operability.
It offers no technical advantages over free Linux distros in the late 2010's, and it is barely impossible to buy a non-Mac computer without paying for it, which should be illegal. European Union, time to use your regulatory powers.
The following anecdote illustrates Windows' pervasiveness. Ciro Santilli was once tutoring a high school student in Brazil, and decided to try and get her into programming. When the "Windows is not free" subject came up, the high school student was shocked: "I paid 100 dollars for this?". She never even knew it was there. To her, it was "just a computer".
Laws should really be passed forcing OEMs to allow you to not buy Microsoft Windows when buying a computer, European Union, why have you failed me in 2016??? en.wikipedia.org/wiki/Bundling_of_Microsoft_Windows
blog.zorinaq.com/i-contribute-to-the-windows-kernel-we-are-slower-than-other-oper/ I Contribute to the Windows Kernel. We Are Slower Than Other Operating Systems. Here Is Why. by Marc Bevand (2013) has some interesting remarks:
There's also little incentive to create changes in the first place. On linux-kernel, if you improve the performance of directory traversal by a consistent 5%, you're praised and thanked. Here, if you do that and you're not on the object manager team, then even if you do get your code past the Ob owners and into the tree, your own management doesn't care. Yes, making a massive improvement will get you noticed by senior people and could be a boon for your career, but the improvement has to be very large to attract that kind of attention.
Bomb disposal robot by The IT Crowd
. Source. Other good lists:
- quantumcomputingreport.com/resources/tools/ is hard to beat as usual.
- www.quantiki.org/wiki/list-qc-simulators
- JavaScript
- algassert.com/quirk demo: github.com/Strilanc/Quirk drag-and-drop, by a 2019-quantum-computing-Googler, impressive. You can create gates. State store in URL.
- github.com/stewdio/q.js/ demo: quantumjavascript.app/
Bibliography:
- www.epcc.ed.ac.uk/whats-happening/articles/energy-efficient-quantum-computing-simulations mentions two types of quantum computer simulation:
The most common approach to quantum simulations is to store the whole state in memory and to modify it with gates in a given order
However, there is a completely different approach that can sometimes eliminate this issue - tensor networks
As en.wikipedia.org/w/index.php?title=ZX-calculus&oldid=1071329204#Diagram_rewriting tries to explain but fails to deliver as usual consider the GHZ state represented as a quantum circuit.
The naive way would be to just do the matrix multiplication as explained at Section "Quantum computing is just matrix multiplication".
However, ZX-calculus provides a simpler way.
And even more importantly, sometimes it is the only way, because in a real circuit, we would not be able to do the matrix multiplication
This is always possible, because we can describe how to do the conversion simply for any of the Clifford plus T gates, which is a set of universal quantum gates.
Then, after we do this transformation, we can start applying further transformations that simplify the circuit.
It has already been proven that there is no efficient algorithm for this (TODO source, someone said P-sharp complete best case)
But it has been proven in 2017 that any possible equivalence between quantum circuits can be reached by modifying ZX-calculus circuits.
There are only 7 transformation rules that we need, and all others can be derived from those, universality.
So, we can apply those rules to do the transformation shown in Wikipedia:
and one of those rules finally tells us that that last graph means our desired state:because it is a Z spider with and .
This is an interesting initiative which has some similarities to Ciro Santilli's OurBigBook project.
The fatal flaw of the initiative in Ciro Santilli's opinion is the lack of user-generated content. We will never get there without UGC and algorithms, never.
Also as of 2021, it mostly useless business courses: learn.saylor.org unfortunately.
But it has several redeeming factors which Ciro Santilli aproves of:
- exam as a service-like
- they have a GitHub: github.com/saylordotorgo
The founder Michael J. Saylor looks a bit crooked, Rich people who create charitable prizes are often crooked comes to mind. But maybe he's just weird.
Michael Saylor interview by Lex Fridman (2022)
Source. At the timestamp:What statement... maybe he's actually not crooked, maybe it was just an accounting mistake... God, why.
When I go, all my assets will flow into a foundation, and the foundation's mission is to make education free for everybody forever.
If only Ciro Santilli knew how to contact him and convince him that his current approach is innefective and that Ciro has something better! Michael, please Google into this page some day, Ciro Santilli needs funding for OurBigBook.com. A hopeless Tweet at: twitter.com/cirosantilli/status/1548350114623660035. Also tried to hit his
saylor@strategy.com. Single particle double slit experiment by 
Ciro Santilli 35 Updated 2025-04-18 +Created 1970-01-01
Ciro Santilli 35 Updated 2025-04-18 +Created 1970-01-01This experiment seems to be really hard to do, and so there aren't many super clear demonstration videos with full experimental setup description out there unfortunately.
For single-photon non-double-slit experiments see: single photon production and detection experiments. Those are basically a pre-requisite to this.
photon experiments:
- aapt.scitation.org/doi/full/10.1119/1.4955173 "Video recording true single-photon double-slit interference" by Aspden and Padgetta (2016). Abstract says using spontaneous parametric down-conversion detection of the second photon to know when to turn the camera on
Non-elementary particle:
- 2019-10-08: 25,000 Daltons
- interactive.quantumnano.at/letsgo/ awesome interactive demo that allows you to control many parameters on a lab. Written in Flash unfortunately, in 2015... what a lack of future proofing!
Experiments that involve sequencing bulk DNA found in a sample to determine what species are present, as opposed to sequencing just a single specific specimen. Examples of samples that are often used:
- river water to determine which bacteria are present, notably to determine if the water is free of dangerous bacteria. A concrete example is shown at: Section "How to use an Oxford Nanopore MinION to extract DNA from river water and determine which bacteria live in it".
- sea water biodiversity: ocean-microbiome.embl.de/companion.html
- food, including searching for desirable microorganisms such as in cheese or bread yeast
- poo, e.g. to study how the human microbiome influences health. There are companies actively working on this, e.g.: www.microbiotica.com/
One related application which most people would not consider metagenomics, is that of finding circulating tumor DNA in blood to detect tumors.
Caused by slipped strand mispairing.
Absorption, spontaneous and stimulated emission by Ciro Santilli 35 Updated 2025-04-18 +Created 1970-01-01
Ciro Santilli 35 Updated 2025-04-18 +Created 1970-01-01The Dirac equation can be derived basically "directly" from the Representation theory of the Lorentz group for the spin half representation, this is shown for example at Physics from Symmetry by Jakob Schwichtenberg (2015) 6.3 "Dirac Equation".
The Diract equation is the spacetime symmetry part of the quantum electrodynamics Lagrangian, i.e. is describes how spin half particles behave without interactions. The full quantum electrodynamics Lagrangian can then be reached by adding the internal symmetry.
As mentioned at spin comes naturally when adding relativity to quantum mechanics, this same method allows us to analogously derive the equations for other spin numbers.
Bibliography:
Deriving The Dirac equation by Andrew Dotson (2019)
Source. Spin is one of the defining properties of elementary particles, i.e. number that describes how an elementary particle behaves, much like electric charge and mass.
The approach shown in this section: Section "Spin comes naturally when adding relativity to quantum mechanics" shows what the spin number actually means in general. As shown there, the spin number it is a direct consequence of having the laws of nature be Lorentz invariant. Different spin numbers are just different ways in which this can be achieved as per different Representation of the Lorentz group.
Video 1. "Quantum Mechanics 9a - Photon Spin and Schrodinger's Cat I by ViaScience (2013)" explains nicely how:
- incorporated into the Dirac equation as a natural consequence of special relativity corrections, but not naturally present in the Schrödinger equation, see also: the Dirac equation predicts spin
- photon spin can be either linear or circular
- the linear one can be made from a superposition of circular ones
- straight antennas produce linearly polarized photos, and Helical antennas circularly polarized ones
- a jump between 2s and 2p in an atom changes angular momentum. Therefore, the photon must carry angular momentum as well as energy.
- cannot be classically explained, because even for a very large estimate of the electron size, its surface would have to spin faster than light to achieve that magnetic momentum with the known electron charge
- as shown at Video "Quantum Mechanics 12b - Dirac Equation II by ViaScience (2015)", observers in different frames of reference see different spin states
Quantum Spin - Visualizing the physics and mathematics by Physics Videos by Eugene Khutoryansky (2016)
Source. Has the property of visiting all descendants before the parent.
The dot product is a positive definite matrix, and so we see that those will have an important link to familiar geometry.
There are unlisted articles, also show them or only show them.