[rguzman]

context: former theoretical physics grad student, dropped out ABD to start a company.

this comment is right on the money on several fronts:

- the Feynman lectures are great after you already understand some of the mechanics of "doing" physics and have some other exposure to the topics, Halliday & Resnick is a better place to start on any one topic

- with infinite time, i'd always follow the approach of learning the math first and then the physics, the book by Boas is pretty good for self study of the minimum necessary math

- there's no real reason to follow a traditional grad school curriculum ala Fowler unless you need to pass quals in a traditional grad school setting

- simulating physical systems on computers is a pretty good exercise, but very time-consuming, avoid if you already spend a lot of time in front of computers

and some thoughts of my own:

- "get a strong foundation in Physics" is a bit too vague to be a useful goal, some examples of potentially better goals: "be able to pass a classical mechanics qual in the allotted time", "be able to write down the standard model and explain it", "be able to grok N papers from the X section of arxiv per week", "be able to write down toy classical field theories and calculate their predictions", ...

- if you are looking to avoid computers, try supplementing your reading with simple experiments either by buying educational kits or by hacking together things

- the books by David Griffiths (esp the E&M one) are awesome

- try to follow curiosity instead of a program: trying to answer "how do superconducting materials work?" for yourself is better than "follow the grad intro to condensed matter that's available online"

- use the physics stackexchange and other forums: asking and answering questions can be very helpful

[godelski]

I'll second Griffiths for E&M, Quantum, and Particle. I think everyone that has gone through a physics undergrad will swear by Griffiths. He is just such a delight.

But I'll suggest Marion and Thornton [0] for Classical. With Griffiths for E&M and Thornton for Classical you should be able to get a really good grasp on most of "physics". I'll also say that these series are upper division for undergrads. Given OP's background I think these would be fine starting points. If not, start with Halliday[1].

For grad level, the gold standard is Goldstein for Classical [2] and Jackson for Electrodynamics[3].

These types of books will give you a very strong base in physics and should enable you to branch out. Given your ML background you may be very interested in thermodynamics and statistical mechanics.

I'll also add an "out there" idea. Sign up for physics classes at your local community college if they offer labs. I say this as someone who went Physics -> CS and is doing HPC + ML. Labs really stress and force you to do analysis. Lower division labs won't ask too much, but if you go in with this intent I think you can get a lot out of it. I'm sure that if you did these lower div labs and talked to a professor at your local uni they would allow you to sit in on upper division labs (you would NEED to show that you are serious first, because these labs can be dangerous! Happy to help you learn doesn't mean happy to babysit and make sure you don't electrocute yourself or making sure you don't take a laser to the eye. TAing undergrad labs I saw enough people get electrocuted, including myself... more than once).

[0] https://smile.amazon.com/Classical-Dynamics-Particles-System...

[1] https://www.smile.amazon.com/Fundamentals-Physics-10th-David...

[2] https://smile.amazon.com/Classical-Mechanics-Goldstein-Poole...

[3] https://smile.amazon.com/Classical-Electrodynamics-Third-Dav...

[psalminen]

Second Griffiths books, I used both his E&M and QM books in undergrad. His voice is excellent.