I'm currently an undergraduate at a prestigious private university in the U.S. I'm majoring in Physics, Math, and Computer Science and currently am a junior. I've taken 5 graduate level courses so far (including Real Analysis and Algorithms) and have undergraduate experience working in a lab in a field unrelated to quantum computing (for which I'm in the process of writing a paper about). I've also taken a course in quantum computing, 2 semester of undergraduate quantum mechanics, 2 semesters of discrete math, and a course on complexity theory. I plan to take 2 semesters of grad quantum in my senior year as well as 2 semesters in mathematical logic.
I'm interested in going to graduate school for theoretical work in quantum computing and quantum information theory. I'm wondering if I should be aiming to apply to Computer Science, Math (Applied I would guess), or Physics departments if I want to do research in those fields.