Hello, I'm still a freshman undergraduate, so it's very early to decide what field of physics I will spend most of my time working in. However, I'm wondering how narrow one's research has to be -- for example, is it feasible to do work in both atomic physics and nuclear physics? How about throwing condensed matter into that mix? Does that answer depends on the nature of the research, i.e. theoretical vs. experimental? Just realized this probably should have been in career guidance, sorry about that.