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Anonymous Wed 18 Aug 15:14:16 2021 No.13532620 View Reply Original Report

Quoted By: >>13532659 >>13532684 >>13532712 >>13532762 >>13532954 >>13533255 >>13533659 >>13535713 >>13535742 >>13536177

"Based" or "Cringed?"

Anonymous

Anonymous Wed 18 Aug 2021 15:16:13 No.13532632 Report

Quoted By:

neither, it outright fucking sucks, as does his other book on E&M

Anonymous

Anonymous Wed 18 Aug 2021 15:17:49 No.13532638 Report

Quoted By:

it's a literally a superposition
based in the sense that it's approachable
cringe in that it doesn't prep you well for big boy QM
read it and move on to more advanced texts, like sakurai
i don't come back to this book, unlike Griffiths' EM book, which i still find useful long after graduating

Anonymous

Anonymous Wed 18 Aug 2021 15:19:02 No.13532642 Report

Quoted By: >>13532652

lol, i was about to add it's the most polarizing physics text i know, in the sense you either like it or hate it. first post proves i was wrong to omit that

Anonymous

Anonymous Wed 18 Aug 2021 15:20:28 No.13532652 Report

Quoted By:

>>13532642
>you either like it or hate it
it's more that you either suck at physics, or you know better alternatives to Griffiths because his books are almost the definition of a meme

Anonymous

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Anonymous Wed 18 Aug 2021 15:22:00 No.13532659 Report

Quoted By: >>13532665 >>13532718

>>13532620
Well in the quantum world it can be both, so it could be referred to as "Bringe" or "Craced", both are valid terms for standard based or cringed superposition problems you'll learn about in undergrad. Hope this helps.

Anonymous

Anonymous Wed 18 Aug 2021 15:23:53 No.13532665 Report

Quoted By:

>>13532659
some top tier bantz right here lads

Anonymous

Anonymous Wed 18 Aug 2021 15:29:40 No.13532684 Report

Quoted By:

>>13532620
cringe

Anonymous

Anonymous Wed 18 Aug 2021 15:36:01 No.13532702 Report

Quoted By:

>cat on the cover
fucking gross

Anonymous

Anonymous Wed 18 Aug 2021 15:38:54 No.13532712 Report

Quoted By:

>>13532620
>Griffiths is standard undergraduate text
>It is standard for undergraduates to be lacking basic understanding of quantum mechanics
I'll let you decide

Anonymous

Anonymous Wed 18 Aug 2021 15:42:06 No.13532718 Report

Quoted By: >>13533125

>>13532659
Neck yourself

Anonymous

Anonymous Wed 18 Aug 2021 16:00:29 No.13532762 Report

Quoted By: >>13532927 >>13533264

>>13532620
It is absolutely terrible for actually developing an understanding of QM. Nonetheless, almost every undergrad curriculum uses it because the students haven't developed enough mathematical sophistication to learn QM properly. Instead, Griffiths relies on the crutch of calculus/diffeq being shoved down students' throats. It's no surprise that the "common" perspective of Schrodinger's equation is as a PDE, when that's not even necessarily true in the first place (the Hamiltonian for spin systems has no Laplacians or whatever). In reality, Schrodinger's equation is either merely a restatement of Stone's theorem (dynamical version, time-independent Hamiltonian), or the generalization of Stone's theorem to monoids (dynamical, time-dependent Hamiltonian), or merely an eigenvalue equation/spectral theorem (static version).

Anonymous

Anonymous Wed 18 Aug 2021 16:49:25 No.13532927 Report

Quoted By: >>13533093

>>13532762
>In reality, Schrodinger's equation is either merely a restatement of Stone's theorem (dynamical version, time-independent Hamiltonian), or the generalization of Stone's theorem to monoids (dynamical, time-dependent Hamiltonian), or merely an eigenvalue equation/spectral theorem (static version).
or, more simply and directly than all that would just be the obvious Hamilton-Jacobi equation when energy is not assumed infinitely divisible...
ironic you complain about Griffiths relying on mathematical crutches and then think Schrodinger's equation should be considered as a mathematical theorem instead of the directly physical thing that it is

Anonymous

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Anonymous Wed 18 Aug 2021 16:56:03 No.13532954 Report

Quoted By: >>13533268 >>13536562

>>13532620
I've never got my hands on a decent QM book.
The first things that come to my mind for each book are:
>Griffiths
Convoluted, confusing, barebones, goes into the wrong direction.
>Landau
Difficult for the sake of being difficult, beautifully written, requires some experience in QM, no braket notation, some amazing proofs
>Sakurai
Too difficult for a beginner, has way too many gaps inbetween/things left unexplained

My prof used Sakurai to base his lectures in my undergrad class. I tried to supplement with Griffiths but it was useless and Landau did provide some useful insight.

Weirdly enough, all 3 books I touched on Quantum Information were great. Nielsen & Chuang is beyond based so are JJJ.

Captcha: Hype?

Anonymous

Anonymous Wed 18 Aug 2021 17:29:09 No.13533093 Report

Quoted By: >>13533117 >>13533124

>>13532927
The fact that you think that the Hamilton-Jacobi equation simply generalizes to the SE literally proves the point of my post. HJ only has connections to QM when you are working in continuous variable QM (position and momentum observables on L^2, etc.). Again, a spin system looks nothing like this and requires a wholly new formalism, beyond merely quantizing position and momentum coordinates to operators.
Furthermore I don't know what you really mean when you say
>when energy is not assumed infinitely divisible
Because there are certainly Hamiltonians with continuous spectra that have no proper classical equivalent (periodic systems and their band gaps are a good example). The discreteness of energies is not sufficient to fully generalize from classical to quantum.

Anonymous

Anonymous Wed 18 Aug 2021 17:34:35 No.13533117 Report

Quoted By: >>13533229

>>13533093
>The fact that you think that the Hamilton-Jacobi equation simply generalizes to the SE literally proves the point of my post.
It does, it's literally the most direct way of making contact between classical and quantum mechanics.
Trying to introduce Stones theorem and monoids when the topic of the thread is an undergrad physics text is nothing more than absolute pseudo intellectual masturbation. They're supposed to be learning physics, not how to make something simple look abstract so it looks like you've done something when you haven't.

Anonymous

Anonymous Wed 18 Aug 2021 17:37:05 No.13533124 Report

Quoted By: >>13533229

>>13533093
>Furthermore I don't know what you really mean when you say
>>when energy is not assumed infinitely divisible
Also this is probably because of too much time spent on mathematical wank, since it's absolutely clear what is meant by that.
The eikonal equation Hamilton derived is the Schrodinger equation except Hamilton took what we would now call Plancks constant to be 0. When you know energy comes in quanta, you don't do this, and thus get Schrödinger's equation directly from Hamilton Jacobi theory, hence the old quantum theory using action angle variables.

Anonymous

Anonymous Wed 18 Aug 2021 17:37:22 No.13533125 Report

Quoted By:

>>13532718
u first

Anonymous

Anonymous Wed 18 Aug 2021 18:00:30 No.13533229 Report

Quoted By: >>13536556

>>13533117
No, it doesn't. It leads to the SE equation with a particular Hamiltonian $H = \sum_i \frac{\nabla_i^2}{2m_i} + V$ . I'll concede if you can show me how to obtain an arbitrary self-adjoint operator (of any Hilbert space dimension) from HJ.
Sure, you don't need to be as rigorous as talk about Stone's theorem. My point was more that there is a clear algebraic/functional analytic way of talking about QM, and that von Neumann showed us decades ago, and that most working physicists actually use. Tricking undergrads into thinking that quantum is just "solve a PDE" is disingenuous and does nothing to help them understand finite-dimensional QM.
>>13533124
>mathematical wank
Please. What I posted is hardly anything sophisticated, except maybe the mention of monoids (would you be happier if I used a Dyson series explanation instead?). As for you point about the HJ equation, see above.

Anonymous

Anonymous Wed 18 Aug 2021 18:08:17 No.13533255 Report

Quoted By:

>>13532620
Giga fucking cringe. Griffith's QM is probably the worst physics textbook ever. If you want a good QM textbook get sakurai.

Anonymous

Anonymous Wed 18 Aug 2021 18:12:10 No.13533264 Report

Quoted By:

>>13532762
Seriously, the amount of undergrads that don't this shit is painful, especially since it makes QM slightly more intuitive imo.

Anonymous

Anonymous Wed 18 Aug 2021 18:13:44 No.13533268 Report

Quoted By:

>>13532954
sakurai isn't too difficult for a beginner desu, its just fine.

Anonymous

Anonymous Wed 18 Aug 2021 18:23:19 No.13533302 Report

Quoted By:

My undergrad used Cohen-Tannoudji, it's OK

Anonymous

Anonymous Wed 18 Aug 2021 20:08:08 No.13533659 Report

Quoted By:

>>13532620
It's great for students and pisses off pseuds so I'd say pretty based.

Anonymous

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Anonymous Thu 19 Aug 2021 10:51:21 No.13535713 Report

Quoted By:

>>13532620
at least it explains things rather than pulling random shit out from the ass like picrel.

Anonymous

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Anonymous Thu 19 Aug 2021 11:20:00 No.13535742 Report

Quoted By:

>>13532620
I had this book when I did my intro to QM class.
I thought it was fine. QM is pretty interesting, I'd have probably taken more QM courses if I could've scheduled it, but alas the final semesters of my bachelor were already beyond full

Anonymous

Anonymous Thu 19 Aug 2021 14:57:30 No.13536177 Report

Quoted By:

>>13532620
I liked it as a first course on QM, as other have said however it is pretty shallow. His other books are trash through, his Electrodynamics book almost caused me to fail my EM exam. If anyone cares Zangwill is superior in every way.

Also since this is a textbook thread anyone got any good recommendations for stat mech?

Anonymous

Anonymous Thu 19 Aug 2021 15:35:36 No.13536294 Report

Quoted By:

>le meme cat on the cover
Fuckin cringe. And yes, I do judge a book by its cover.

Anonymous

Anonymous Thu 19 Aug 2021 16:46:31 No.13536556 Report

Quoted By:

>>13533229
All of this is covered without being named as Stone's theorem anyway, and there isn't a single person alive who comes out of a physics course not being aware you don't need to just view quantum mechanics as a PDE. For an undergrad's first contact there is nothing wrong with introducing the Schrodinger equation in a particular way instead of being needlessly general and depriving them of physical intuition for the subject.
That said, Griffiths does neither, so it's a shit book.

Anonymous

Anonymous Thu 19 Aug 2021 16:49:22 No.13536562 Report

Quoted By:

>>13532954
Bohm's book for undergrads explains a lot of the concepts very well. It's barely used because I think people dont want to associate too much with his more fringe ideas but it was a standard text once upon a time.
One of the worst texts might actually be Weinberg, surprisingly enough.

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