Mathematical preparation: calculus, mathematical physics methods, group theory

Basic physics: mechanics, heat, optics, electromagnetism, atomic physics/modern physics.

Dielectric Physics: "Four Mechanics"-Theoretical Mechanics, Electrodynamics, Quantum Mechanics, Thermodynamics and Statistical Physics,

In addition, there are solid physics and computational physics.

Advanced physics: relativity, advanced quantum mechanics, quantum field theory, advanced statistics, nuclear physics, particle physics.

The above courses are compulsory courses for theoretical physics majors. After reading it all, it is basically an introduction.

Generally speaking, learning theoretical physics does not need any foundation, from easy to difficult, step by step, and if you stick to it, you will get something.