The first diodes. These were apparently incredibly unreliable, especially for portable radios, as you had to randomly search for the best contact point you could find in a random polycrystalline material!!
And also quality was highly dependant on where the material was sourced from as that affected the impurities present in the material. Later this was understood to be an issue of doping.
It was so unreliable that vacuum tube diodes overtook them in many applications, even though crystal detectors are actually semiconductor diodes, which eventually won over!
For a long time, before artificial semiconductors kicked in, people just didn't know the underlying physical working principle of these detectors. What I cannot create, I do not understand basically.
A measurable function defined on a closed interval is square integrable (and therefore in ) if and only if Fourier series converges in norm the function:
Theory that describes electrons and photons really well, and as Feynman puts it "accounts very precisely for all physical phenomena we have ever observed, except for gravity and nuclear physics" ("including the laughter of the crowd" ;-)).
While Ciro acknowledges that QED is intrinsically challenging due to the wide range or requirements (quantum mechanics, special relativity and electromagnetism), Ciro feels that there is a glaring gap in this moneyless market for a learning material that follows the Middle Way as mentioned at: the missing link between basic and advanced. Richard Feynman Quantum Electrodynamics Lecture at University of Auckland (1979) is one of the best attempts so far, but it falls a bit too close to the superficial side of things, if only Feynman hadn't assumed that the audience doesn't know any mathematics...
The funny thing is that when Ciro Santilli's mother retired, learning it (or as she put it: "how photons and electrons interact") was also one of her retirement plans. She is a pharmacist by training, and doesn't know much mathematics, and her English was somewhat limited. Oh, she also wanted to learn how photosynthesis works (possibly not fully understood by science as that time, 2020). Ambitious old lady!!!
Combines special relativity with more classical quantum mechanics, but further generalizing the Dirac equation, which also does that: Dirac equation vs quantum electrodynamics. The name "relativistic" likely doesn't need to appear on the title of QED because Maxwell's equations require special relativity, so just having "electro-" in the title is enough.
Before QED, the most advanced theory was that of the Dirac equation, which was already relativistic but TODO what was missing there exactly?
As summarized at: youtube.com/watch?v=_AZdvtf6hPU?t=305 Quantum Field Theory lecture at the African Summer Theory Institute 1 of 4 by Anthony Zee (2004):
- classical mechanics describes large and slow objects
- special relativity describes large and fast objects (they are getting close to the speed of light, so we have to consider relativity)
- classical quantum mechanics describes small and slow objects.
- QED describes objects that are both small and fast
That video also mentions the interesting idea that:Therefore, for small timescales, energy can vary a lot. But mass is equivalent to energy. Therefore, for small time scale, particles can appear and disappear wildly.
- in special relativity, we have the mass-energy equivalence
- in quantum mechanics, thinking along the time-energy uncertainty principle,
QED is the first quantum field theory fully developed. That framework was later extended to also include the weak interaction and strong interaction. As a result, it is perhaps easier to just Google for "Quantum Field Theory" if you want to learn QED, since QFT is more general and has more resources available generally.
Like in more general quantum field theory, there is on field for each particle type. In quantum field theory, there are only two fields to worry about:
- photon field
- electromagnetism field
Lecture 01 | Overview of Quantum Field Theory by Markus Luty (2013)
Source. This takes quite a direct approach, one cool thing he says is how we have to be careful with adding special relativity to the Schrödinger equation to avoid faster-than-light information.Good modern OpenGL tutorial in retained mode with shaders, see also: stackoverflow.com/questions/6733934/what-does-immediate-mode-mean-in-opengl/36166310#36166310
Joe Corneli, of of the contributors, mentions this in a cool-sounding "Peeragogy" context at metameso.org/~joe/:
I earned my doctorate at The Open University in Milton Keynes, with a thesis focused on peer produced support for peer learning in the mathematics domain. The main case study was planetmath.org; the ideas also informed the development of “Peeragogy”.
Understanding Electromagnetic Radiation! by Learn Engineering (2019)
Source. Shows animations of a dipole antenna which illustrates well how radiation is emitted from moving charges and travels at the speed of light.- James Legge (1891):
- ctext.org/zhuangzi side by side with Chinese, one chapter per page. Dividies it into three parts:
- Inner Chapters
- Outer Chapters
- Miscellaneous Chapters
- ctext.org/zhuangzi side by side with Chinese, one chapter per page. Dividies it into three parts:
There's a bit of both sides in the 2016 race:
- tx 3aaae4adc68b3768e1a6029987f2aca2479818495c9aee6a86067710806e9c4f: "bEW Trump 2016! Stop the TPP!"
- tx 202ceac7b3e7b990d1961fd2eab18ba5c80c99f10eacc783f14c53ebfdcaee00 "oEW Fuck Obama&Clinton Go Trump!!!!"
- tx 53fcddaa69e79c0fdc4e2cd139bffef341a38d46bb653721d9adf42460b1afae "EW Trump will fail America, like all his businesses"
- data/out/0433.txt:1752:EW FUCK Trump and his supporters. You ppl are the dumbest scum ever.
- data/out/0435.txt:1904:EW TRUMP 2016 !!!!!!!!!!!!!!
- data/out/0437.txt:1150:bjEW FuCk OfF TrUmP!
- data/out/0439.txt:1017:EW trump will trample regulations justly
- data/out/0443.txt:1281:L9,GOD EMPEROR TRUMP WINS THIRD TERM`7
- data/out/0444.txt:2102:L99,TRUMPPPPPPPPPPPPPPP
- data/out/0445.txt:311:L127,TRUMP WILL SAVE THE WORLD.
- data/out/0445.txt:1257:EW Howard not Trump is the actual 45th president.
- tx 2fb07a8f358d690d8717734a48e5daf0ef70ea2d0e3b7c88dace8a5818fcb168 "L299,Trump touched my no-no"
- data/out/0457.txt:8677:EW All of the sheep think Donald Trump is literally Hitler.
- data/out/0481.txt:11481:I kill donald trump!!!!!!
- data/out/0545.txt:1239:}fEW fuck donald trump
- tx 05fce37228c732f4635f79e6f36d028be677404beab497ddace9024fe8e4b517 "EW Heil Trump!He's the true white leader our race need so much since Adolf"
- data/out/0552.txt:14:Trump needs to get impeached and locked up!
- data/out/0666.txt:56:(Trump was impeached for the second time in office.
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