Specific type of Josephson junction. Probably can be made tiny and in huge numbers through photolithography.
Illustration of a thin-film superconducting tunnel junction (STJ)
Source. The superconducting material is light blue, the insulating tunnel barrier is black, and the substrate is green.
Quantum Transport, Lecture 14: Josephson effects by Sergey Frolov (2013)
Source. youtu.be/-HUVGWTfaSI?t=878 mentions maskless electron beam lithography being used to produce STJs.When Ciro Santilli was studying electronics at the University of São Paulo, the courses, which were heavily inspired from the USA 50's were obsessed by this one! Thinking about it, it is kind of a cool thing though.
That Wikipedia page is the epitome of Wikipedia failure to explain things in a way that is of any interest to any learner. Video 1. "Tutorial on LC resonant circuits by w2aew (2012)" is the opposite.
Tutorial on LC resonant circuits by w2aew (2012)
Source. - youtu.be/hqhV50852jA?t=239 series LC circuit on a breadboard driven by an AC source. Shows behaviour on oscilloscope as source frequency is modified. We clearly see voltage going to zero at resonance. This is why thie circuit can be seen as a filter.
- youtu.be/hqhV50852jA?t=489 shows the parallel LC circuit. We clearly see current reaching a maximum on resonance.
LC circuit dampened oscillations on an oscilloscope by Queuerious Guy (2014)
Source. Finally a video that shows the oscillations without a driving AC source. The dude just move wires around on his breadboard manually, first charging the capacitor and then closing the LC circuit, and is able to see damped oscillations on the oscilloscope.Introduction to LC Oscillators by USAF (1974)
Source. - youtu.be/W31CCN_ZF34?t=740 mentions that LC circuit formation is the root cause for Audio feedback with a quick demo. Not very scientific, but cool.
LC circuit by Eugene Khutoryansky (2016)
Source. Exactly what you would expect from an Eugene Khutoryansky video. The key insight is that the inductor resists to changes in current. So when current is zero, it slows down the current. And when current is high, it tries to keep it going, which recharges the other side of the capacitor.Once upon a time young Ciro Santilli spent lots of time evaluating the features of different terimnals. The many windows of Terminator. The pop-uppiness of Guake/Yakuake.
But then one day he met tmux, and he was enlightened
Terminal choice doesn't matter. Just use tmux.
www.threekit.com/blog/gltf-everything-you-need-to-know comparision of several formats
Complex analogue of orthogonal matrix.
Applications:
- in quantum computers programming basically comes down to creating one big unitary matrix as explained at: quantum computing is just matrix multiplication
Piezoelectric, and notably used in quartz clock.
Editor. As last time. And the one before. But now it is for real.
I guess ended up doing all the "how things should look like" features because they clarify what the website is supposed to do, and I already have my own content to bring it alive via
ourbigbook --web upload.But now I honestly feel that all the major elements of "how things should look like" have fallen into place.
And yeah, nobody else is never going to contribute as things are! WYSIWYG is a must.
I was really impressed by Trillium Notes. I should have checked it long ago. The UI is amazing, and being all Js-based, could potentially be reused for our purposes. The project itself is a single-person/full trust notetaking only for now however, so not a direct replacement to OurBigBook.
The growing number of parameters of the Standard Model is one big source of worry for early 21st century physics, much like the growing number of particles was a worry in the beginning of the 20th (but that one was solved by 2020).
Why do symmetries such as SU(3), SU(2) and U(1) matter in particle physics? Updated 2025-03-28 +Created 1970-01-01
Physicists love to talk about that stuff, but no one ever has the guts to explain it into enough detail to show its beauty!!!
Perhaps the wisest thing is to just focus entirely on the part to start with, which is the quantum electrodynamics one, which is the simplest and most useful and historically first one to come around.
Perhaps the best explanation is that if you assume those internal symmetries, then you can systematically make "obvious" educated guesses at the interacting part of the Standard Model Lagrangian, which is the fundamental part of the Standard Model. See e.g.:
- derivation of the quantum electrodynamics Lagrangian
- Physics from Symmetry by Jakob Schwichtenberg (2015) chapter 7 "Interaction Theory" derives all three of quantum electrodynamics, weak interaction and quantum chromodynamics Lagrangian from each of the symmetries!
One bit underlying reason is: Noether's theorem.
Notably, axelmaas.blogspot.com/2010/08/global-and-local-symmetries.html gives a good overview:so it seems that that's why they are so key: local symmetries map to the forces themselves!!!
A local symmetry transformation is much more complicated to visualize. Take a rectangular grid of the billiard balls from the last post, say ten times ten. Each ball is spherical symmetric, and thus invariant under a rotation. The system now has a global and a local symmetry. A global symmetry transformation would rotate each ball by the same amount in the same direction, leaving the system unchanged. A local symmetry transformation would rotate each ball about a different amount and around a different axis, still leaving the system to the eye unchanged. The system has also an additional global symmetry. Moving the whole grid to the left or to the right leaves the grid unchanged. However, no such local symmetry exists: Moving only one ball will destroy the grid's structure.Such global and local symmetries play an important role in physics. The global symmetries are found to be associated with properties of particles, e. g., whether they are matter or antimatter, whether they carry electric charge, and so on. Local symmetries are found to be associated with forces. In fact, all the fundamental forces of nature are associated with very special local symmetries. For example, the weak force is actually associated in a very intricate way with local rotations of a four-dimensional sphere. The reason is that, invisible to the eye, everything charged under the weak force can be characterized by a arrow pointing from the center to the surface of such a four-dimensional sphere. This arrow can be rotated in a certain way and at every individual point, without changing anything which can be measured. It is thus a local symmetry. This will become more clearer over time, as at the moment of first encounter this appears to be very strange indeed.
axelmaas.blogspot.com/2010/09/symmetries-of-standard-model.html then goes over all symmetries of the Standard Model uber quickly, including the global ones.
Philosophically, machine learning can be seen as a form of lossy compression.
And if we make it too lossless, then we are basically overfitting.
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