why you can't explain qcd

"Angela Collier is my favourite YouTube science communicator" - Albert Einstein

"You can't explain it to a six year old because it takes 4 years of undergrad and 4 years of grad school-" Ok, so they must be at LEAST 8 years old. Got it.

"Those are cartoons. They're not math." Angela shoving a category theorist into his locker.

I would like to propose that "Quantum Gastrodynamics" is a way better term for weak force flavor interactions.

The video really delivers on its promise, at the beginning of my shower I didn't understand QCD and at the end of my shower I still do not understand QCD.

“Albert Einstein catching strays from Dr. Collier is one of my favorite things about this channel.” - Mark Twain

I don't know if you have ever tried to explain something to a 6 year old, but they will ask you why about a thousand times while you are explaining something. To me, this is the root of the quote. It is not about being able to get the 6 year old to understand or have them be able to explain in the future. It is about being able to answer all of their why questions. If you can accurately answer all of their questions then you fully understand the subject.

The more I listen to Dr Collier, the more I realize I don't know shit about fuck but also the more I enjoy realizing this about myself. Dr Collier is a superhero. Her power is knowledge. Her secret weapon is an anti-crackpot-Dunning-Krueger-syndrome-theorists mischievous smile. Thank you so much.

Watching at 2x speed so I can not understand QCD in less than 20 mins

> sign up for a qcd lecture > Ask the professor if it's really about qcd or if it's just qed > They don't understand > Prepare a half hour YouTube video about the difference between qcd and qed > They laugh "it's a qcd lecture" > Attend > It's all qed

My mental model of the relative complexity: QED: watching 2 or 3 billiard balls run into each other on a nice smooth pool table. QCD: watching a writhing ball of spaghetti the size of the solar system and oh yeah, the spaghetti is moving at nearly the speed of light and is made up of super-powerful magnets.

"wait, this video has nothing to do with war. why am i here?" - Sun Tzu

“W boson?? More like L bozo”— my attempt at a joke

"Doesn't that suck for Einstein?...People just make stuff up and they say Einstein said it." -Albert Einstein

Einstein once said: "I have predicted many things in my life. My theory can predict Mercury's precession. My theory predicts black holes. But the prediction I am most proud off is that 12 year olds will incorrectly attribute quotes to me on the internet."

I'm really glad that this professional science communicator was able to ensure I understood that I do not understand QCD.

At CalTech in 1970 (and probably in his books later) Feynman described trying to tell his father, an intelligent layperson, about what he did. I remember Feynman telling how, when his father asked “when the neutron becomes an electron and a proton, was the electron always there ‘inside’ the neutron?” “And I couldn’t explain it to him.”

“ I’m saying words but math math math.” I think I need a T-shirt that says this.

I like Feynman's opposite quote: "If I could explain it simply, it wouldn't be worth a Nobel Prize."

One of the problems is that the approach that makes the leap from QED to QCD seem simple and natural is a really mathematically abstract one, where you take gauge symmetry as the most important thing that determines the whole theory. Usually when you study electromagnetism in a quantum mechanics class, gauge symmetry comes in kind of late as an advanced topic. If you express electromagnetism as potentials, you can do things to the potentials and simultaneously do something to the phases of the matter wave functions, and it's unchanged even if you do it differently at every point in space-time. And then you turn it on its head and say that gauge symmetry is what determines electromagnetism--you start with the relativistic QM of matter particles, then add gauge symmetry and the potentials have to come in, then you somehow breathe life into those and treat them as aspects of a physical field and you've got QED. Then you say, well, the gauge symmetry involved a mathematical object called a Lie group, and for QED the group is the simplest nontrivial one you can use, "U(1)", which is actually the same as a circle (messing with phases of the wave function, which go in a circle). Then you go from "messing with the phase" to "messing with some multidimensional space of color charges", which is a different Lie group, and QCD falls out, and then you mess with other quantities (the "flavordynamics" stuff Angela was talking about) and a big chunk of the Standard Model falls out. And whether the force carrying field has charge has to do with whether the group operations are commutative. But the class has this big mountain climb to even get to that point and it's very abstract. How do you even do that in an elementary context? I haven't quite figured it out. I recall Heinz Pagels trying in his book "The Cosmic Code", but it was a stretch.