Condensed matter physics Updated +Created
Condensed matter physics is one of the best examples of emergence. We start with a bunch of small elements which we understand fully at the required level (atoms, electrons, quantum mechanics) but then there are complex properties that show up when we put a bunch of them together.
Includes fun things like:
As of 2020, this is the other "fundamental branch of physics" besides to particle physics/nuclear physics.
Condensed matter is basically chemistry but without reactions: you study a fixed state of matter, not a reaction in which compositions change with time.
Just like in chemistry, you end up getting some very well defined substance properties due to the incredibly large number of atoms.
Just like chemistry, the ultimate goal is to do de-novo computational chemistry to predict those properties.
And just like chemistry, what we can actually is actually very limited in part due to the exponential nature of quantum mechanics.
Also since chemistry involves reactions, chemistry puts a huge focus on liquids and solutions, which is the simplest state of matter to do reactions in.
Condensed matter however can put a lot more emphasis on solids than chemistry, notably because solids are what we generally want in end products, no one likes stuff leaking right?
But it also studies liquids, e.g. notably superfluidity.
One thing condensed matter is particularly obsessed with is the fascinating phenomena of phase transition.
Figure 1.
xkcd 2933: Elementary Physics Paths
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Video 1.
What Is Condensed matter physics? by Erica Calman
. Source. Cute. Overview of the main fields of physics research. Quick mention of his field, quantum wells, but not enough details.
Einstein notation for partial derivatives Updated +Created
The Einstein summation convention works will with partial derivatives and it is widely used in particle physics.
In particular, the divergence and the Laplacian can be succintly expressed in this notation:
In order to expresse partial derivatives, we must use what Ciro Santilli calls the "partial index partial derivative notation", which refers to variales with indices such as , , , , and instead of the usual letters , and .
Gamma ray Updated +Created
Most commonly known as a byproduct radioactive decay.
Their energy is very high compared example to more common radiation such as visible spectrum, and there is a neat reason for that: it's because the strong force that binds nuclei is strong so transitions lead to large energy changes.
A decay scheme such as Figure "caesium-137 decay scheme" illustrates well how gamma radiation happens as a byproduct of radioactive decay due to the existence of nuclear isomer.
Gamma rays are pretty cool as they give us insight into the energy levels/different configurations of the nucleus.
They have also been used as early sources of high energy particles for particle physics experiments before the development of particle accelerators, serving a similar purpose to cosmic rays in those early days.
But gamma rays they were more convenient in some cases because you could more easily manage them inside a laboratory rather than have to go climb some bloody mountain or a balloon.
The positron for example was first observed on cosmic rays, but better confirmed in gamma ray experiments by Carl David Anderson.
Haascope Updated +Created
By Andy Haas, an experimental particle physics professor: as.nyu.edu/content/nyu-as/as/faculty/andy-haas.html What an awesome dude!
Video 1.
Haasoscope prototype, 2 4-channel boards
. Source.
Lagrangian mechanics Updated +Created
Originally it was likely created to study constrained mechanical systems where you want to use some "custom convenient" variables to parametrize things instead of global x, y, z. Classical examples that you must have in mind include:
When doing lagrangian mechanics, we just lump together all generalized coordinates into a single vector that maps time to the full state:
where each component can be anything, either the x/y/z coordinates relative to the ground of different particles, or angles, or nay other crazy thing we want.
The Lagrangian is a function that maps:
to a real number.
Then, the stationary action principle says that the actual path taken obeys the Euler-Lagrange equation:
This produces a system of partial differential equations with:
  • equations
  • unknown functions
  • at most second order derivatives of . Those appear because of the chain rule on the second term.
The mixture of so many derivatives is a bit mind mending, so we can clarify them a bit further. At:
the is just identifying which argument of the Lagrangian we are differentiating by: the i-th according to the order of our definition of the Lagrangian. It is not the actual function, just a mnemonic.
Then at:
  • the part is just like the previous term, just identifies the argument with index ( because we have the non derivative arguments)
  • after the partial derivative is taken and returns a new function , then the multivariable chain rule comes in and expands everything into terms
However, people later noticed that the Lagrangian had some nice properties related to Lie group continuous symmetries.
Basically it seems that the easiest way to come up with new quantum field theory models is to first find the Lagrangian, and then derive the equations of motion from them.
For every continuous symmetry in the system (modelled by a Lie group), there is a corresponding conservation law: local symmetries of the Lagrangian imply conserved currents.
Genius: Richard Feynman and Modern Physics by James Gleick (1994) chapter "The Best Path" mentions that Richard Feynman didn't like the Lagrangian mechanics approach when he started university at MIT, because he felt it was too magical. The reason is that the Lagrangian approach basically starts from the principle that "nature minimizes the action across time globally". This implies that things that will happen in the future are also taken into consideration when deciding what has to happen before them! Much like the lifeguard in the lifegard problem making global decisions about the future. However, chapter "Least Action in Quantum Mechanics" comments that Feynman later notice that this was indeed necessary while developping Wheeler-Feynman absorber theory into quantum electrodynamics, because they felt that it would make more sense to consider things that way while playing with ideas such as positrons are electrons travelling back in time. This is in contrast with Hamiltonian mechanics, where the idea of time moving foward is more directly present, e.g. as in the Schrödinger equation.
Furthermore, given the symmetry, we can calculate the derived conservation law, and vice versa.
And partly due to the above observations, it was noticed that the easiest way to describe the fundamental laws of particle physics and make calculations with them is to first formulate their Lagrangian somehow: why do symmetries such as SU(3), SU(2) and U(1) matter in particle physics?s.
Bibliography:
Video 1.
Euler-Lagrange equation explained intuitively - Lagrangian Mechanics by Physics Videos by Eugene Khutoryansky (2018)
Source. Well, unsurprisingly, it is exactly what you can expect from an Eugene Khutoryansky video.
Leonard Susskind Updated +Created
The bald confident chilled out particle physics guy from Stanford University!
One can't help but wonder if he smokes pot or not.
Also one can't stop thinking abot Leonard Hofstadter from The Big Bang Theory upoen hearing his name.
Figure 1.
Leonard Susskind lecturing in 2013
. Source.
Open University Updated +Created
Not really dedicated to open source course material, nor to free courses...
The "Open" in its name only made sense in the 60's, when it was founded, nowadays, there isn't much about this institution that is very different compared to traditional Oxbridge. "Cheap more online university" would be a more adequate name for it.
A system that would truly live up to the name "Open" in the year 2020 is the one described at the ideal university by Ciro Santilli.
Wikipedia even says that the initial focus was on broadcasting learning material on television and radio, so what happened to that now that we have an even more powerful on-demand tool called Internet!
They even created their own MOOC website, FutureLearn. But www.freecodecamp.org/news/massive-open-online-courses-started-out-completely-free-but-where-are-they-now-1dd1020f59/ mentions:
The course content is still free to access, but it’s only available for the duration of the course, and for two weeks after it ends.
OMG. God why.
A few open sources at: www.open.edu/openlearn/free-courses. The 5-hour course on particle physics says it all. Stated as of 2023 at www.open.ac.uk/about/open-educational-resources/openlearn/free-learning:
The OU provides around 5% of its formal course materials as free open educational content every year on OpenLearn
www.youtube.com/watch?v=Pj0rbafFBak What's an Open University Degree Like? by Luke Cutforth (2021) mentions that it is more autodidactic/online, and it encourages part time learning.
youtu.be/rsWwffX-u0A?t=99 Open University - How does it work? by Matt Greg Vlogs (2017) shows that they do have their own custom institutional material. And it is not open???? Please. youtu.be/rsWwffX-u0A?t=222 mentions that there is no entry exam, and you can change your courses at any time, that is good at least.
Israel apparently also created their own version in the 70's inspired by the British one: Open University of Israel. Same story it seems.
How to convince teachers to use CC BY-SA Updated +Created
A major difficulty of getting such this to work is that may university teachers want to retain closed copyright of their work because they:
Therefore the only way is to find teachers who are:
  • enlightened to use such licenses
  • forced by their organizations to use such licenses
The forced option therefore seems like a more bulk efficient starting point for searches.
No matter how much effort a single person puts into writing perfect tutorials, they will never beat 1000x people + an algorithm.
It is not simply a matter of how much time you have. The fundamental reason is that each person has a different background and different skills. Notably the young students have radically different understanding than that of the experienced teacher.
Therefore, those that refuse to contribute to such platforms, or at least license their content with open licenses, will inevitably have their work forgotten in favor of those that have contributed to the more open platform, which will eventually dominate everything.
Perhaps OurBigBook.com is not he killer platform that will make this happen. Perhaps the world is not yet ready for it. But Ciro believes that this will happen, sooner or later, inevitable, and he wants to give it a shot.
Also worth checking:
Figure 1. Source. Convincing academics that their tutorial are not always perfect is one of blocking points to the acceptance of solutions such as OurBigBook.com. To thrive in the competition of academia, those people are amazing at publishing novel results. Explaining to beginners however, not necessarily so.
Physics Travel Guide Updated +Created
DokuWiki about physics, mostly/fully written by Jakob Schwichtenberg and therefore focusing on particle physics, although registration might be open to all.
Ron Maimon Updated +Created
Ron Maimon is a male human theoretical physicist with an all but dissertation started in 1995 at Cornell University[ref][ref].
Figure 1.
Ron Maimon's Physics Stack Exchange profile picture
. Source.
Ron is mostly known for simultaneously:
Ron seems to share a few philosophies which Ciro greatly agrees with as part of Cirism, which together with his knowledge of physics, make Ciro greatly respect Ron. Such philosophies include:
However he also subscribes to some theories which Ciro Santilli considers conspiracy theories, e.g. his ideas about the Boston Marathon bombing that got him banned from Quora (a ban which Ciro strongly opposes due to freedom of speech concerns!), but the physics might be sound, Ciro Santilli does not know enough physics to judge, but it often feels that what he says makes sense.
chat.stackexchange.com/transcript/message/7104585#7104585 mentions that he was at Cornell University and did all but dissertation, but he mentions that he was still self-taught:
Eugene Seidel: On your personal info page you write that you are not a physics Ph.D. but does that mean you were a physics undergrad in college then went to grad school and finished ABD... or are you entirely self taught?
Ron Maimon: ABD. I am self- taught though, I only went to school for accreditation. I had a thesis worth of work at the time I left grad-school,
Eugene Seidel: ok thanks
Ron Maimon: I was just kind of sickened by academic stuff that was going on--- large extra dimensions were popular then.
Eric Walker: Anyway, thanks Ron -- I'll get back to you with more questions soon, I'm sure.
Ron Maimon: Also I was at Cornell, my advisor left for Cincinnatti, and I was not in very good standing there (I was kind of a jerk, as I still am). Some friends wanted to start a biotech company called "Gene Network Sciences", and I joined them.
This is corroborated e.g. at: web.archive.org/web/20201226171231/http://pages.physics.cornell.edu/~gtoombes/Student_Index.html (original pages.physics.cornell.edu/~gtoombes/Student_Index.html down as of 2023).
At youtu.be/ObXbKbpkSjQ?t=2454 from Video 1. "Ron Maimon interview with Jeff Meverson (2014)" he mentions his brother is a professor. At physics.stackexchange.com/questions/32382/could-we-build-a-supercomputer-out-of-wires-and-switches-instead-of-a-microchip confirms that his brother's name is "Gaby Maimon", so this neuroscience professor at the Rockerfeller University is likely him: www.rockefeller.edu/our-scientists/heads-of-laboratories/985-gaby-maimon/. Looks, age, location and research interest match.
Bibliography:
  • gmachine1729.livejournal.com/161418.html Ron Maimon answers about physics and math on Quora (part 1) by Sheng Li (2020) contains a selection of some amazing Ron Maimon posts
  • www.reddit.com/r/RonMaimon/ someone made a Reddit for him. Less than 100 users as of 2022, but has potential.
  • some Quora threads about him, oh the irony:
    • www.quora.com/Is-Ron-Maimon-actually-a-pioneer-or-a-jest
    • www.quora.com/Are-Ron-Maimons-answers-on-mathematics-physics-and-computer-science-factually-correct
    • www.quora.com/What-do-people-think-of-Ron-Maimons-paper-Computational-Theory-of-Biological-Function-I
    • www.quora.com/Who-is-Ron-Maimon/answer/Ron-Maimon
      I'm a physics grad school drop-out working in theoretical biology but I still do physics when I get a chance, but not right now because I am in a middle of a project to understand the properties of a certain virus as completely as possible.
      Also in a comment he explains something to a now deleted comment, presumably asking why he dropped out of grad school, and gives a lot more insight:
      It's a complicated boring story.
      I dropped out mainly to do biology with friends at a startup, because I figured out how you're supposed to do theory in biology, but also I truly believe it was next to impossible for me to get a degree without selling out, and I would rather be shot than write a paper with an idea I don't believe.
      My grad school phase was a disaster. I first worked for Eric Siggia, but I got away because he had me do something boring and safe, I figured I have only a limited number of years before I turn 30 and my brain rots, and I wasn't going to sell out and do second-rate stuff. I found a young guy at the department doing interesting things (Siggia was also doing interesting things, like RNA interactions, he just wouldn't assign any of them to ME), this was Philip Argyres, and got him to take me. Argyres wanted me to work on large-extra dimensions (this was 1998), but I made it clear to him that I would rather be boiled in oil. I worked a little bit on a crappy experimental setup that didn't work at all, because I didn't know enough about electromagnetic screening nor about how to set up experiment. But EVERYONE LOVED IT! This is also how I knew it was shit. Good work is when everyone hates it. But I learned Lifschitz's ideas for quantum electrodynamics in media from this project.
      Me and every competent young person in high-energy physics knew large extra dimensions was a fraud on the day it came out, and I had no intention of doing anything except killing the theory. Once Wikipedia appeared, I did my best to kill it by exposing it's charlatanry on the page for large extra dimension. That was in 2005 (after getting fired from the company), and from this point onward large-extra-dimensions lost steam. But I can't tell how much of this was my doing.
      Argyres liked N=2 theory, and we did something minor in N=2 SUSY models around 2000, but I was bogged down here, because I was trying to do Nicolai map for these, and it ALMOST worked for years, but it never quite worked. But I knew from the moduli interpretation and Seiberg-Witten solution that it must work. If I live long enough, I'll figure it out, I am still sure it isn't hard. But this was the link to statistical stochastic models, the work I was doing with Jennifer Schwarz, and I wanted to link up the two bodies of work (they naturally do through Nicolai map).
      But I had my own discovery, the first real discovery I made, in 1999, this thing that I called the mass-charge inequality, what Vafa and Motl called "the weakest-force principle" when they discovered it in 2006. It was swampland, and Vafa hadn't yet begun swampland. My advisor didn't believe my result was correct, because he saw me say many stupid things before this. So he wouldn't write it or develop it with me (but I had read about Veltman telling 'tHooft he couldn't publish the beta-function, I knew Argyres was wrong about this)
      Anyway, Argyres left for Cincinnatti in 2000, and I joined the company then. I was in the company until january 2005. Then they fired me, which was ok, by then it was a miserable hell-hole full of business types.
      I discovered Wikipedia, and started killing large extra dimensions. I wanted to finish my thesis, and some people agreed to help me do this, but I had told myself "no thesis until you get the Nicolai map sorted out" and I never did. I worked with Chris Henley a little bit, who wanted me to do some stuff for him, and I discovered an interesting model for high-Tc, but Henley said it was out of fasion, and nobody would care, even though I knew it was the key to the phenomenon (still unpublished, but soon).
      This was 2008-2009, and I became obsessed with cold fusion, so Henley dropped me, as I had clearly gone crazy. I developed the theory of cold fusion during the last weeks of working for Henley. Then I dropped out for good.
      Honestly, by the time I was gone, I realized that the internet would make a degree counterproductive, because I knew I had better internet writing skills than any of the old people, I was a Usenet person. Online, the degrees and accreditation were actually a hinderance. So by this point, I secretly preferred not to have a PhD, because I knew I was good at physics, and I could attack from the outside and win. It's not too hard if you know the technical material.
      The only problem is that I was unemployed and isolated in Ithaca for about 7 years after having gone through my first productive phase. But I developed the cold-fusion ideas in this period, I learned a lot of mathematics, and I developed a ton of biology ideas that are mostly unpublished, but will be published soon. It astonished people that I could have no degree and be unemployed and have such a sky-high ego. The reason is that I could evaluate my own stuff, and I liked it!
Backlinks:
Video 1.
Ron Maimon interview with Jeff Meverson (2014)
Source. Ripped from Jeff's "Quoracast": player.fm/series/quoracast-podcast/ron-maimon-truther Ron mentions he was an early-Usenet user. Key points:
Standard Model Updated +Created
As of 2019, the more formal name for particle physics, which is notably missing general relativity to achieve the theory of everything.
cds.cern.ch/record/799984/files/0401010.pdf The Making of the Standard Model by Steven Weinberg mentions three crucial elements that made up the standard model post earlier less generalized quantum electrodynamics understandings
Weak interaction Updated +Created
Explains beta decay. TODO why/how.
Maybe a good view of why this force was needed given beta decay experiments is: in beta decay, a neutron is getting split up into an electron and a proton. Therefore, those charges must be contained inside the neutron somehow to start with. But then what could possibly make a positive and a negative particle separate?
www.thestargarden.co.uk/Weak-nuclear-force.html gives a quick and dirty:
Beta decay could not be explained by the strong nuclear force, the force that's responsible for holding the atomic nucleus together, because this force doesn't affect electrons. It couldn't be explained by the electromagnetic force, because this does not affect neutrons, and the force of gravity is far too weak to be responsible. Since this new atomic force was not as strong as the strong nuclear force, it was dubbed the weak nuclear force.
Also interesting:
While the photon 'carries' charge, and therefore mediates the electromagnetic force, the Z and W bosons are said to carry a property known as 'weak isospin'. W bosons mediate the weak force when particles with charge are involved, and Z bosons mediate the weak force when neutral particles are involved.
Video 1. Source. Some decent visualizations of the field lines.