FTX Updated 2025-07-16
Imperial College London Updated 2025-07-16
Nice, nice place. Natural sciences only, no bullshit.
ITER Updated 2025-07-16
Lysergic acid diethylamide Updated 2025-07-16
National Ignition Facility Updated 2025-07-16
The best technology YouTube channels Updated 2025-07-16
You can learn more from older students than from faculty Updated 2025-07-16
Wikipedia mentions quoting his Nobel Prize biography:
Depth of a quantum circuit Updated 2025-07-16
This is an important metric, because it takes some time for the quantum operations to propagate, and so the depth of a circuit gives you an idea of how long the coherence time a hardware needs to support a given circuit.
Bibliography:
Library of Alexandria Updated 2025-07-16
License Updated 2025-07-16
Lie algebra exponential covering problem Updated 2025-07-16
Lie Groups, Physics, and Geometry by Robert Gilmore (2008) 7.2 "The covering problem" gives some amazing intuition on the subject as usual.
Mathieu group Updated 2025-07-16
University of Cambridge Updated 2025-07-16
The Questioning City by British Pathé (1963)
Source. Located in Cambridge, United Kingdom.
Second largest number of Nobel Prize as of 2019, need on say more? en.wikipedia.org/w/index.php?title=List_of_Nobel_laureates_by_university_affiliation&oldid=934987075
Animal rights Updated 2025-07-16
Ciro Santilli has mixed feelings about animal rights.
On one hand, his irrational side wants of course all animals to be happy.
On the other, he does not care about this enough to not kill and eat them, even though he believes that you could live off plants relatively well.
His more rational side says: humans are sacred. Either because you believe in the soul, or because your built-in empathy behaviours. If it is not a human, do whatever you want to it. Killing is already undoubtedly the greatest sin. It is not OK to kill a human painlessly is it? So if torturing it brings humans good, then do it.
Of course, this does get use close and closer to "the what is a human" question, which is more relevant than ever in the awakening of genetics: all species are after all a continuum right?
And Ciro does not have a simple solution to this problem, besides that in 99.9999% the answer is obvious to 99.9999% of the people, and for the others cases, we have to do it like the law and make flawed rules to cover the remaining 0.000099999% cases and let juries decide the rest.
The only other sensible sacredness barrier is the common vegetarian "nervous systems are sacred" one. But how can you believe that if you also follow the religion of physics, where everything is just made of atoms?
Is it evil to take one neuron and torture it? What does that even mean? It will be fun when pain and pleasure are fully understood.
And you are going to have a really hard time when mosquitoes start transmitting deadly diseases that kill your family.
Laws in most 2020 Western modern societies have converged to a hypocritical balance between not offending people too much by hiding the killing and minimizing the pain when possible at low cost. Killing animals painlessly is basically always fine if it brings any "non sadistic" pleasure to humans. And torturing animals is fine with approval e.g. to make medicines.
This has the downside of increasing costs for society. Maybe there are practical benefits besides people feeling bad about animals? Maybe we would have more serial killers if people were free to torture animals? Maybe people in butcher shops would become depressive if their bosses weren't forced to use more expensive painless killing methods? Neither of those seems like huge arguments though.
It eventually comes down to: "how much more is a human life worth than that of an animal" which brings Jesus's Matthew 6:25-34 "Do Not Worry" (archive) quote to mind:
Therefore I tell you, do not worry about your life, what you will eat or drink; or about your body, what you will wear. Is not life more than food, and the body more than clothes? Look at the birds of the air; they do not sow or reap or store away in barns, and yet your heavenly Father feeds them. Are you not much more valuable than they?
Non-vegetarian pets owners also baffle Ciro, as most of them basically extend the sacred human line further arbitrarily to certain other cute looking animals like dogs, cats or rabbits, but will gladly kill a cow indirectly by paying someone to pay someone to pay someone to cut it into small pieces. Or they believe that certain specific individuals are sacred. Admittedly, the latter is more rational, and looks a lot of how we treat our own families well, and can accept that other families are not doing so well.
Ciro's even more rational evil side says: the real reason why humans are sacred is a practical one: people have families that love them, and they come to kill you if you kill them, and this starts endless chains of violence that make society unbearable.
Derivation of the Dirac equation Updated 2025-07-16
The 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:
Oxford Brookes University Updated 2025-07-16
Their only undergraduate courses that matter:
United States diplomatic cables leak Updated 2025-07-16
University of Edinburgh Updated 2025-07-16
Cocaine Updated 2025-07-16
Derivation of the quantum electrodynamics Lagrangian Updated 2025-07-16
Like the rest of the Standard Model Lagrangian, this can be split into two parts:
- spacetime symmetry: reaches the derivation of the Dirac equation, but has no interactions
- add the internal symmetry to add interactions, which reaches the full equation
Deriving the qED Lagrangian by Dietterich Labs (2018)
Source. As mentioned at the start of the video, he starts with the Dirac equation Lagrangian derived in a previous video. It has nothing to do with electromagnetism specifically.
He notes that that Dirac Lagrangian, besides being globally Lorentz invariant, it also also has a global invariance.
However, it does not have a local invariance if the transformation depends on the point in spacetime.
He doesn't mention it, but I think this is highly desirable, because in general local symmetries of the Lagrangian imply conserved currents, and in this case we want conservation of charges.
To fix that, he adds an extra gauge field (a field of matrices) to the regular derivative, and the resulting derivative has a fancy name: the covariant derivative.
Then finally he notes that this gauge field he had to add has to transform exactly like the electromagnetic four-potential!
So he uses that as the gauge, and also adds in the Maxwell Lagrangian in the same go. It is kind of a guess, but it is a natural guess, and it turns out to be correct.
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