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A 9-line summary of textbook physics

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Re: A 9-line summary of textbook physics

#91

Post by whimsicalism »

gus_massa wrote: post #71
323 wrote: post #41

I've read a few times that you can derive the Maxwell equations from knowing that U(1) exists, as this article implies, that every point in space has (among other things) the symmetry of a circle. But I've never seen this derivation. I assume it's either trivial or too complicated. Anyone has a link or thoughts on this?

I wrote an ELI25 explanation in a comment a few months ago, and I'll copy it here: In quantum mechanics the wave function Ψ is has complex values. If you multiply everything in the universe by -1, nothing changes because all the physical results use ΨΨ* (where * is the complex conjugation). You can also multiply everything by i or -i. Moreover by any other complex number of modulo 1 because ΨΨ* does not change. (The…

What does it mean to "add a new field A"? Add to what? The wave function?

Re: A 9-line summary of textbook physics

#92

Post by roywiggins »

whimsicalism wrote: post #90
ravi-delia wrote: post #37

Earlier quoted context omitted.

I think the way these are phrased do a better job expressing the "vibe", for lack of a better word, of our current understanding. That the particles and constants are declared by fiat, with behavior constrained by simpler laws, is an understanding I didn't come to until I took a QFT course. The physicist's God is as concerned with forbidding seemingly pointless things as the biologist's God is with beetles.

It is interesting that we humans have so much difficulty breaking away from anthropomorphizing.

If large chunks of our brainpower are actually hardwired to think in terms of other humans¹, anthropomorphism might just be a strategy to recruit those hardwired systems into helping out with other tasks.

¹ this may not be true

Re: A 9-line summary of textbook physics

#93

Post by emerged »

None of us can discount the possibility that the universe was fine tuned with a specific set of seed parameters which yields a specific trajectory including all of the narrative elements of one person or everyone’s lives.

Most likely the big narrative payoff is somebody winning the claw game for once at the local sports bar. But which of us will it be for?

Re: A 9-line summary of textbook physics

#95

Post by _Nat_ »

PrettyPebble wrote: post #86
_Nat_ wrote: post #79

Earlier quoted context omitted.

It's not that they're " wrong " so much as that they're incoherent and largely non-sense. Sorry if that seems harsh, just.. this looks like someone's having some sort of crisis. It's worrisome.

No, it is fun! The scientists who are looking for exceptions to the standard model and to general relativity since 50 years are having a crisis at present, as often told. The 9 lines imply all equations of physics. Every Lagrangian of physics is included. The lines are also coherent: none contradicts another. They are complementary: the cover all observations and all fields of physics. No field of physics is left out…

Those 9-lines don't imply all of physics. They don't even mention most of physics. A lesser problem is that they're not correct, either.

For example, Line-5 suggests that entropy is never below the Boltzmann-constant. Which simply isn't true; there're notions of zero-entropy, where zero is less than the Boltzmann-constant.

For another example, Line-2 suggests that nature itself is local; this would contradict non-local effects, e.g. entanglement, and would seem to prohibit faster-than-light recession.

Or, maybe those lines were meant in a way that doesn't have those problems? But maybe they have different problems? Who knows! -- which is the bigger problem.

This is usually described as ["not even wrong"](https://en.wikipedia.org/wiki/Not_even_wrong ). Because, to be wrong, it'd have to make more sense first.

Re: A 9-line summary of textbook physics

#96

Post by blablabla123 »

_Nat_ wrote: post #79
PrettyPebble wrote: post #75

Earlier quoted context omitted.

If the 9 lines are wrong, just show it... Thousands of scientists are trying the same since 50 years.

It's not that they're " wrong " so much as that they're incoherent and largely non-sense. Sorry if that seems harsh, just.. this looks like someone's having some sort of crisis. It's worrisome.

I mean you have the groups (6. and 7.) from there you get all the variables. E.g. from U(1) you get the generator and the group item. Then add all combinations of the polynomes to L (1.) but skip those that violate invariances like Lorentz (2.), U(1), SU(2), SU(3). You end up with something like L=-1/2 d phi^2 - m phi^2. (Oversimplified) Do the same for SU(2) and SU(3) and you end up with http://nuclear.ucdavis.edu/~tgutierr/files/sml2.pdf For convenience usually some of the variables are then called e (Electron), W+ (W+ Boson) etc.

Re: A 9-line summary of textbook physics

#97

Post by a_e_k »

MauranKilom wrote: post #9

> About 18 particles > About 25 numbers Excellent science here!

I take this to be an acknowledgement that we don't know everything.

I.e.,

    "These are the only ones of which the news has come to Haaahrvard,
    And there may be many others but they haven't been discohhhvered."

Re: A 9-line summary of textbook physics

#98

Post by Itti »

marginalia_nu wrote: post #76
smoyer wrote: post #48

Earlier quoted context omitted.

You're assuming free will isn't some complex-looking behavior driven by quantum uncertainty. In the multiverse, every social scientist has many clones who's studies refute their work!

Even if that is so, a quantum description of human behavior is fairly useless in terms of practical application. How does knowledge of the standard model cure the infirm, prevent crime, and so forth?

When we exhibit behaviors. Our context is derived from our visual/auditory field processing from birth. Those waves implant magnetic field signatures on our neurotransmitter morphologies. We are almost explicitly operational in quantum activity. Many if not all disabilities or health complications are resonant to your mind body homeostasis. Challenge the quantum spectral development process of a person you solve the aforementioned issues.

Re: A 9-line summary of textbook physics

#99

Post by dbsmith83 »

vixen99 wrote: post #85
sdoering wrote: post #26

Earlier quoted context omitted.

> Do not use a marker, a pen or a pencil to highlight or underline text on paper. It is a waste of time, provides false comfort and makes the text unreadable. What a load of elitist BS (pardon my French). When I was at University we were trained early on to cut the notion of a book being sacred. We should mark, note, create meaning on the pages with pens. I would not have been able to learn as much in my life if I ha…

I think the author does have a point though it clearly doesn't apply to everyone. 'Elitist BS' is rather strong. You take a different view but perhaps you've never studied in a part of the world where books are in short supply and one expensive copy is shared. I underlined passages in books in the past and now regret imposing my then partial view via permanent marking. Just a thought but a cataclysmic extinction even…

If a cataclysmic extinction event occurred, I doubt a little bit of highlighting or underlining is going to cause significant burden on mankind's ability to relearn things. I do agree though, that if you don't own the book you probably shouldn't mark in it.
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