São Paulo City Updated 2025-07-16
Although Ciro Santilli lived in São Paulo City nominally during his studies, it would be more precise to say that he lived in University of São Paulo-land, because Ciro was cheap, didn't have a car, and did nothing but study, stay at home, go back to Santos to see his parents and the beach.
But the little he saw of the city made a deep impression on him.
The unreasonable size.
The unbearable contrasts.
Caetano's Sampa is the ultimate description of the city!
satoshi@vistomail.com Updated 2025-07-16
One of Satoshi's email addresses, it's how he made the First public announcement of Bitoin on first public announcement of Bitcoin on 2008-10-31.
At some point later on vistomail.com was discontinued and acquired by a super dodgy dude, Alex Elbanna, so it hasn't been Satoshi for a while.
Nvidia GPU Updated 2025-07-16
Quantum Processes and Computation course of the University of Oxford Updated 2025-07-16
2022 page: www.cs.ox.ac.uk/teaching/courses/2022-2023/quantum/ (archive). Assignments are available:
- www.cs.ox.ac.uk/people/aleks.kissinger/courses/qpc2022/assignment1.pdf
- www.cs.ox.ac.uk/people/aleks.kissinger/courses/qpc2022/assignment2.pdf
- www.cs.ox.ac.uk/people/aleks.kissinger/courses/qpc2022/assignment3.pdf
- www.cs.ox.ac.uk/people/aleks.kissinger/courses/qpc2022/assignment4.pdf
- www.cs.ox.ac.uk/people/aleks.kissinger/courses/qpc2022/assignment5.pdf
- www.cs.ox.ac.uk/people/aleks.kissinger/courses/qpc2022/assignment6.pdf
2022 lecturer: Aleks Kissinger
The course would be better named ZX-calculus as it appears to be the only subject covered.
Quantum physics by Jim Branson (2003) Updated 2025-07-16
Last updated: 2013.
There were apparently some lecture videos at: web.archive.org/web/20030604194654/http://physicsstream.ucsd.edu/courses/spring2003/physics130a/ as pointed out by Matthew Heaney[ref], .mov files can be found at: web.archive.org/web/*/http://physicsstream.ucsd.edu/courses/spring2003/physics130a/*, but we were yet unable to open them, related:
Open Textbook Library Updated 2025-07-16
Make a bug report for a crash on Ubuntu Updated 2025-07-16
On Ubuntu 23.10, a crash led to the creation of:After that simply running apport-cli as: led to the creation of: bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/2049368 a bug on the
/var/crash/_usr_bin_gnome-shell.1000.crashapport-cli gnome-shellgnome-shell package. Laucnh Amazin EC2 with existing EBS volume Updated 2025-07-16
Google Chrome Updated 2025-07-16
GitHub awesome repo Updated 2025-07-16
Quantum number Updated 2025-07-16
Quantum numbers appear directly in the Schrödinger equation solution for the hydrogen atom.
However, it very cool that they are actually discovered before the Schrödinger equation, and are present in the Bohr model (principal quantum number) and the Bohr-Sommerfeld model (azimuthal quantum number and magnetic quantum number) of the atom. This must be because they observed direct effects of those numbers in some experiments. TODO which experiments.
E.g. The Quantum Story by Jim Baggott (2011) page 34 mentions:This refers to forbidden mechanism. TODO concrete example, ideally the first one to be noticed. How can you notice this if the energy depends only on the principal quantum number?
As the various lines in the spectrum were identified with different quantum jumps between different orbits, it was soon discovered that not all the possible jumps were appearing. Some lines were missing. For some reason certain jumps were forbidden. An elaborate scheme of ‘selection rules’ was established by Bohr and Sommerfeld to account for those jumps that were allowed and those that were forbidden.
College of the University of Cambridge Updated 2025-07-16
Scalable Vector Graphics Updated 2025-07-16
Companies have been really slow to support SVG features in their browsers, and that is very saddening: medium.com/@michaelmangial1/introduction-to-scalable-vector-graphics-6450c03e8d2e
You can't drop SVG support for
canvas until there's a way to run untrusted JavaScript on the browser!SVG does have some compatibility annoyances, notably SVG fonts. But we should as a society work to standardize and implement a fix those, the benefits of SVG are just too great!
Examples:
- svg/svg.svg a minimal somewhat sane SVG:
- if the
widthandheightproperties were not given, you get the default 300x150, which seems to be set in the SVG standard:
- if the
- how to add na SVG image to a HTML file:
- svg/svg.html: external image. The included file is svg/svg.svg.
- svg/inline.html: inline.
- svg/billion-laughs.svg
- svg/html.svg
- svg/triangle.svg
- svg/viewBox.svg: this attribute allows you to control the default SVG
svg width=andheight=while keeping the coordinates of the drawing untouched. If theviewBoxaspect ratio differs from the width/height ratio, you likely want to play withpreserveAspectRatio, otherwise you would get white spaces by default on the generated image - CSS with SVG:
- svg/style.svg: inline CSS
- svg/style-external.svg: external CSS with:
<?xml-stylesheet type="text/css" href="svg.css" ?>, see also: stackoverflow.com/questions/18434094/how-to-style-svg-with-external-css- svg/subdir/style-external.html: is the relative CSS relative to the HTML or to the SVG? Answer: to the SVG... OMG. So how to make it work reliably?
- svg/current-color.html and svg/current-color.svg: illustrates
fill="currentColor". Only works for inline SVG however... See also: stackoverflow.com/questions/13000682/how-do-i-have-an-svg-image-inherit-colors-from-the-html-document/13002311
- JavaScript with SVG:
- svg/defs.html hows how
defsworks- svg/defs-external.html tries to include external
defsfrom svg/defs.svg, but that fails like everything else related to external SVGs
- svg/defs-external.html tries to include external
Scalar (mathematics) Updated 2025-07-16
A member of the underlying field of a vector space. E.g. in , the underlying field is , and a scalar is a member of , i.e. a real number.
Scanning electron microscope Updated 2025-07-16
The Scanning Electron Microscope by MaterialsScience2000 (2014)
Source. Shows operation of the microscope really well. Seems too easy, there must have been some extra setup before however. Impressed by how fast the image update, it is basically instantaneous. Produced by Prof. Dr.-Ing. Rainer Schwab from the Karlsruhe University of Applied Sciences.Mosquito Eye Scanning Electron Microscope Zoom by Mathew Tizard (2005)
Source. Video description mentions is a composite video. Why can't you do it in one shot? Quantum mechanics Updated 2025-07-16
Quantum mechanics is quite a broad term. Perhaps it is best to start approaching it from the division into:
- non-relativistic quantum mechanics: obviously the simpler one, and where you should start
- relativistic quantum mechanics: more advanced, and arguably "less useful"
Key experiments that could not work without quantum mechanics: Section "Quantum mechanics experiment".
Mathematics: there are a few models of increasing precision which could all be called "quantum mechanics":
Ciro Santilli feels that the largest technological revolutions since the 1950's have been quantum related, and will continue to be for a while, from deeper understanding of chemistry and materials to quantum computing, understanding and controlling quantum systems is where the most interesting frontier of technology lies.
Quantum logic gates are needed for physical implementation Updated 2025-07-16
One direct practical reason is that we need to map the matrix to real quantum hardware somehow, and all quantum hardware designs so far and likely in the future are gate-based: you manipulate a small number of qubits at a time (2) and add more and more of such operations.
While there are "quantum compilers" to increase the portability of quantum programs, it is to be expected that programs manually crafted for a specific hardware will be more efficient just like in classic computers.
TODO: is there any clear reason why computers can't beat humans in approximating any unitary matrix with a gate set?
This is analogous to what classic circuit programmers will do, by using smaller logic gates to create complex circuits, rather than directly creating one huge truth table.
The gates themselves are just unitary matrices that operate on the input qubits and produce the same number of output qubits.
For example, the matrix for the CNOT gate, which takes 2 qubits as input is:
1 0 0 0
0 1 0 0
0 0 0 1
0 0 1 0The final question is then: if I have a 2 qubit gate but an input with more qubits, say 3 qubits, then what does the 2 qubit gate (4x4 matrix) do for the final big 3 qubit matrix (8x8)? In order words, how do we scale quantum gates up to match the total number of qubits?
The intuitive answer is simple: we "just" extend the small matrix with a larger identity matrix so that the sum of the probabilities third bit is unaffected.
More precisely, we likely have to extend the matrix in a way such that the partial measurement of the original small gate qubits leaves all other qubits unaffected.
For example, if the circuit were made up of a CNOT gate operating on the first and second qubits as in:
0 ----+----- 0
|
1 ---CNOT--- 1
2 ---------- 2TODO lazy to properly learn right now. Apparently you have to use the Kronecker product by the identity matrix. Also, zX-calculus appears to provide a powerful alternative method in some/all cases.
ipinf.ru Updated 2025-07-16
Connect to other computer in LAN by hostname Updated 2025-07-16
There are unlisted articles, also show them or only show them.