STED microscopy Updated 2025-07-16
Instead of shining a light over the entire sample to saturate it, you illuminate just a small bit instead.
He was basically saying that this truly brings the resolution to the actual physical limits, going much much beyond 2014 Nobel prize levels.
Street reclamation Updated 2025-07-16
Only people who need to drive a car should be allowed to drive a car anywhere near a city, e.g. people who work door to door, people who are disabled, etc.
Countryside driving is fine. If going to a city, you just have to drive to a parking outside of the city where you then take the public transport. And those who live in cities must leave their cars there too.
Everyone else must walk or cycle from home to public transport.
Cars just destroy everything, they make everything ugly:
- this was extremely clear to Ciro Santilli as a cyclist. He previously lived in a place with few cars and the countryside was so pleasant. Then he moved to a place with more cars and it was shocking. It's a mixture of pollution, noise, and the fact that roads cut up the countryside that just make things not pleasant at all. Dual lane roads in particular are just a terrible thing. You can hear them from afar, much before you see them.
- even within cities, cars completely dehumanize the streets. For example, Ciro once lived in a small dead end street, and he would have gladly opened his front window more often to meet the neighbours. But just the noise of cars passing by every so often makes it impractical to work like that.
The Zatoichi effect applies well to the problem of cyclists:This is the main drama faced by cyclists.
- they are not really pedestrians, and pedestrian paths are not suitable to them because they are too narrow, of not smooth, or curved. But pedestrians will always have enough political power to have their paths, because they live around the paths
- they are not really motor vehicles, because motor vehicle paths are too wide and too fast for them. But motor vehicles will always have enough political power to have their paths, because people are lazy and stupid, and because as the world stands, individually you just don't have any reasonable choice to go anywhere.
Lobbying groups:
stress-ng Updated 2025-07-16
Sun Microsystems Updated 2025-07-16
Although Ciro Santilli is a bit past their era, there's an aura of technical excellence about those people. It just seems that they sucked at business. Those open source hippies. Erm, wait.
Bibliography:
- archive.org/details/sunburstascentof00hall Sunburst: the ascent of Sun Microsystems by Mark Hall (1990)
Sun Wukong Updated 2025-07-16
Only after Ciro became an adult did he finally understand that Sun Wukong was the basis for Dragon Ball as mentioned at: Figure "19th century illustration of the Journey to the West protagonist Sun Wukong". And that Sun Wukong was a million times more famous overall. Mind blown.
His given name "Wukong" literally means "the one who mastered the void" (Wu = Comprehend, Kong = void), so clearly a Dharma name. Edit: it is actually given in the novel, he was born without name. They seem to be Taoist however.
The family name sun1 孙 is the same character as "grandson", but most educated Chinese people seem to be able to recognize it as a reference to "monkey" from some archaic context not anymore in current usage.
Superconducting magnet Updated 2025-07-16
Applications: produce high magnetic fields forAs of the early 2020s, superconducting magnets predominantly use low temperature superconductors Nb-Ti and Nb-Sn, see also most important superconductor materials, but there were efforts underway to create practical high-temperature superconductor-based magnets as well: Section "High temperature superconductor superconducting magnet".
- magnetic resonance imaging, the most important commercial application as of the early 2020s
- more researchy applications as of the early 2020s:
Wikipedia has done well for once:
The current to the coil windings is provided by a high current, very low voltage DC power supply, since in steady state the only voltage across the magnet is due to the resistance of the feeder wires. Any change to the current through the magnet must be done very slowly, first because electrically the magnet is a large inductor and an abrupt current change will result in a large voltage spike across the windings, and more importantly because fast changes in current can cause eddy currents and mechanical stresses in the windings that can precipitate a quench (see below). So the power supply is usually microprocessor-controlled, programmed to accomplish current changes gradually, in gentle ramps. It usually takes several minutes to energize or de-energize a laboratory-sized magnet.
Superconducting qubits are good because superconductivity is macroscopic Updated 2025-07-16
Superconducting qubits are regarded as promising because superconductivity is a macroscopic quantum phenomena of Bose Einstein condensation, and so as a macroscopic phenomena, it is easier to control and observe.
This is mentioned e.g. in this relatively early: physicsworld.com/a/superconducting-quantum-bits/. While most quantum phenomena is observed at the atomic scale, superconducting qubits are micrometer scale, which is huge!
Physicists are comfortable with the use of quantum mechanics to describe atomic and subatomic particles. However, in recent years we have discovered that micron-sized objects that have been produced using standard semiconductor-fabrication techniques – objects that are small on everyday scales but large compared with atoms – can also behave as quantum particles.
Superconducting tunnel junction Updated 2025-07-16
Specific type of Josephson junction. Probably can be made tiny and in huge numbers through photolithography.
Superconductivity Updated 2025-07-16
Experiments:
- "An introduction to superconductivity" by Alfred Leitner originally published in 1965, source: www.alfredleitner.com/
- Isotope effect on the critical temperature. hyperphysics.phy-astr.gsu.edu/hbase/Solids/coop.html mentions that:
If electrical conduction in mercury were purely electronic, there should be no dependence upon the nuclear masses. This dependence of the critical temperature for superconductivity upon isotopic mass was the first direct evidence for interaction between the electrons and the lattice. This supported the BCS Theory of lattice coupling of electron pairs.
20. Fermi gases, BEC-BCS crossover by Wolfgang Ketterle (2014)
Source. Part of the "Atomic and Optical Physics" series, uploaded by MIT OpenCourseWare.Actually goes into the equations.
Notably, youtu.be/O_zjGYvP4Ps?t=3278 describes extremely briefly an experimental setup that more directly observes pair condensation.
The Map of Superconductivity by Domain of Science
. Source. Lacking as usual, but this one is particularly good as the author used to work on the area as he mentions in the video.Lecture notes:
Transition into superconductivity can be seen as a phase transition, which happens to be a second-order phase transition.
Super Mario 64 A press challenge Updated 2025-07-16
Sylvain Poirier Updated 2025-07-16
Ciro Santilli feels a bit like this guy:
- he's also an idealist, even more than Ciro. So cute. Notably, he he also dumps his brain online into pages that no-one will ever read
- he also thinks that the 2010's education system is bullshit, e.g. settheory.net/learnphysics
- trust-forum.net/ some kind of change the world website. But:is a sin to Ciro. Planning a change the world thing behind closed doors? Really? Decentralized, meh.
- antispirituality.net/ his atheism website
singlesunion.org/ so cute, he's looking for true love!!! This is something Ciro often thinks about: why it is so difficult to find love without looking people in the eye. The same applies to jobs to some extent. He has an Incel wiki page: incels.wiki/w/Sylvain_Poirier :-)
Sylvester's law of inertia Updated 2025-07-16
The main interest of this theorem is in classifying the indefinite orthogonal groups, which in turn is fundamental because the Lorentz group is an indefinite orthogonal groups, see: all indefinite orthogonal groups of matrices of equal metric signature are isomorphic.
It also tells us that a change of basis does not the alter the metric signature of a bilinear form, see matrix congruence can be seen as the change of basis of a bilinear form.
The theorem states that the number of 0, 1 and -1 in the metric signature is the same for two symmetric matrices that are congruent matrices.
For example, consider:
The eigenvalues of are and , and the associated eigenvectors are:symPy code:and from the eigendecomposition of a real symmetric matrix we know that:
A = Matrix([[2, sqrt(2)], [sqrt(2), 3]])
A.eigenvects()Now, instead of , we could use , where is an arbitrary diagonal matrix of type:With this, would reach a new matrix :Therefore, with this congruence, we are able to multiply the eigenvalues of by any positive number and . Since we are multiplying by two arbitrary positive numbers, we cannot change the signs of the original eigenvalues, and so the metric signature is maintained, but respecting that any value can be reached.
Note that the matrix congruence relation looks a bit like the eigendecomposition of a matrix:but note that does not have to contain eigenvalues, unlike the eigendecomposition of a matrix. This is because here is not fixed to having eigenvectors in its columns.
But because the matrix is symmetric however, we could always choose to actually diagonalize as mentioned at eigendecomposition of a real symmetric matrix. Therefore, the metric signature can be seen directly from eigenvalues.
What this does represent, is a general change of basis that maintains the matrix a symmetric matrix.
Symmetry breaking in superconductors Updated 2025-07-16
As mentioned in True Genius: The Life and Science of John Bardeen page 224, the idea of symmetry breaking was a major motivation in Josephson's study of the Josephson effect.
Synthetic geometry of the real projective plane Updated 2025-07-16
It good to think about how Euclid's postulates look like in the real projective plane:
- Since there is one point of infinity for each direction, there is one such point for every direction the two parallel lines might be at. The parallel postulate does not hold, and is replaced with a simpler more elegant version: every two lines meet at exactly one point.One thing to note however is that ther real projective plane does not have angles defined on it by definition. Those can be defined, forming elliptic geometry through the projective model of elliptic geometry, but we can interpret the "parallel lines" as "two lines that meet at a point at infinity"
- points in the real projective plane are lines in
- lines in the real projective plane are planes in .For every two projective points there is a single projective line that passes through them.Note however that not all lines in the real plane correspond to a projective line: only lines tangent to a circle at zero do.
Unlike the real projective line which is homotopic to the circle, the real projective plane is not homotopic to the sphere.
The topological difference bewteen the sphere and the real projective space is that for the sphere all those points in the x-y circle are identified to a single point.
One more generalized argument of this is the classification of closed surfaces, in which the real projective plane is a sphere with a hole cut and one Möbius strip glued in.
Synthetic virus Updated 2025-07-16
Man-made virus!
TODO: if we had cheap de novo DNA synthesis, how hard would it be to bootstrap a virus culture from that? github.com/cirosantilli/cirosantilli.github.io/issues/60
Is it easy to transfect a cell with the synthesized DNA, and get it to generate full infectious viral particles?
If so, then de novo DNA synthesis would be very similar to 3D printed guns: en.wikipedia.org/wiki/3D_printed_firearms.
It might already be possible to order dissimulated sequences online:
Tensor product in quantum computing Updated 2025-07-16
We don't need to understand a super generalized version of tensor products to know what they mean in basic quantum computing!
Intuitively, taking a tensor product of two qubits simply means putting them together on the same quantum system/computer.
The quantum state is called a separable state, because it can be written as a single product of two different qubits. We have simply brought two qubits together, without making them interact.
If we then add a CNOT gate to make a Bell state:we can now see that the Bell state is non-separable: we've made the two qubits interact, and there is no way to write this state with a single tensor product. The qubits are fundamentally entangled.
Term of the University of Oxford Updated 2025-07-16
Each term has 8 weeks, and the week number is often used to denote the time at which something happens.
Week 0 is also often used to denote the week before classes officially start. This is especially important in the first term of the year (Michaelmas term) where people are coming back to school and meeting old and new friends.
At the end of the year, after Trinity term, students have exams. These basically account for all of the grades. In certain courses such as the Physics course of the University of Oxford, there is only new material on Michaelmas term and Hilary term, Trinity term being revision-only. So you can imagine that during Trinity term, students are going to be on edge.
Bibliography:
- cherwell.org/2023/11/10/oxfords-term-structure-needs-to-change-heres-why-it-wont/ some criticism of the term organization on Cherwell because the terms are too short which increases student pressure to learn fast
The artist and the politician Updated 2025-07-16
Once upon a time in the 2010's, Ciro Santilli went to an artsy theatre venue in the suburbia of Paris, dragged by his wife then girlfriend of course.
In the venue, there was a politician, who was doing his best to show how much they supported the arts, and there were of course the artists, involved in the play.
The politician would see a political power score on top of every person's head, and would spend an amount of time talking to each person exactly proportional to that score. This meant basically one sentence to us. The words themselves didn't really matter of course, only the time spent, they just have to produce nice sounds.
The art of programming Updated 2025-07-16
Big goals:
- the pursuit of AGI
- physics simulations, including scientific visualization software
- formalization of mathematics
The best Chinese traditional instrumental music Updated 2025-07-16
Wang Jin beats Gao Qiu theme music from The Water Margin featuring a suona solo
. Source. There are unlisted articles, also show them or only show them.