Hey folks. I've been interested in physics for awhile and would like to expand my knowledge. I'm not looking to enroll in college courses, but I would like some good readings to gain more knowledge specifically in the areas of particle physics, dark matter and energy, and string theory. I've taken the intro calculus-based physics courses and modern physics in the past and have a BS in mathematics, so the mathematics isn't my concern. What books and texts would you all recommend for this? Thanks!