I just finished my sophomore year of a 4-year undergrad in Physics, what relevant courses should I take to pursue my career in theoretical physics research? Advanced grad courses are to be recommended too, thanks.
Since most departments are small, there are only a few upper level courses offered each semester. Physics majors should start with those that are required for their degree and unlikely to be offered again before they need to graduate. Advice on which other ones to take depends on which specific courses are offered, which courses one has already completed, and additional details on one's future aspirations.