Dear Physics Forums friends, I am a college senior at US pursuing the mathematics and microbiology majors. Getting to the core of my question, I am curious if the graduate programs in physics (at least in US) also consider applicants from no official background in physics. I started out as an aspiring microbiologist, and I honestly had been hating the art of physics since my high-school years. Due to past research experience related to the bioinformatics (almost a year ago), I acquired huge love to mathematics, which I started to pursue a major in mathematics, and I begun to take various courses like analysis, abstract linear algebra, topology, set theory, etc. The topology course on the last semester introduced me some of fascinating interactions between the mathematics and physics. I think I started to become very curious about physics. Since I am already deeply involved in both math and microbiology majors, I was advised to pursue reading courses in physics, which I am doing right now. Currently, I am doing various reading courses in physics alongside with renowned faculty members, with books like Weinberg, Landau/Lifshitz, etc.; I am also doing reading courses in mathematics like set-theoretic topology and pursuing undergraduate research in machine learning and philosophy of biology. After completing my current research, I am going to take undergraduate research in the theoretical physics with my mentors from mathematics and physics. Since beginning the reading courses in physics, I was enlightened by the power of physics, and I realized that I really love it! The physics is even more interesting that mathematics, microbiology, programming, etc. The theoretical physics and mathematics physics are particularly interesting to me. I am started to really consider preparing for physics graduate programs. Due to ongoing medical treatments, I am going to stay 1.5 years after my senior year (total 5.5 year graduate track). Since I am pursuing two different majors and following medical treatments, my plan is to continue the reading courses in theoretical physics (they are great for building a strong relationship with professors and getting undergraduate projects), and taking some advanced courses in physics, such as relativity and QM. I really regret not discovering my interest to physics earlier than now, which then I would just take physics courses starting from scratch. How should I start to prepare for graduate programs in physics? could you give me some ideas about applications? How can I make my application strong (I am worried that I did not take a lot of physics courses)?