Is it possible (practically, in real life) to pursue two very distinct research interests (e.g. in AI and theoretical physics)? TL;DR: Is it possible to pursue applied research in AI and theoretical physics after a PhD degree in CS focusing on applied AI (as a professor at some universities)?
Long version:
Hello, I'm a 3rd year undergrad at a university in Vietnam.
I've been wondering about the practicality of the above questions for quite some time but I have not yet been able to decide.
For a little bit of background:
I have a fairly good foundation on CS because I have been doing competitive programming since I was 13. Until recently, I feel that research in AI was too applied (I did some research with an advisor on computer vision recently), and then, I discovered theoretical physics and got the feeling that &quot;This is for me,  my true self&quot;.
However, the problem is, in my country, pursuing theoretical research does not really guarantee a stable future career (with good money). So, I'm thinking about doing a PhD in CS focusing on applied AI and self-study physics. After that, I will probably get a position at a university and conduct research in both direction (more focus is put on only one direction, of course).
Can you kindly provide me some pieces of advice for my future career path, or, is my plan possible?
Thank you for spending time reading and answering my question.
It is possible (even “practically, in real life”) to do all sorts of things that are very difficult to do, like: publish five bestselling novels; climb the highest mountain in every continent; win a gold medal in the Olympics; become a successful movie actor; etc etc.
The point is that questions like yours (which seem to get asked here regularly) are very difficult to give a meaningful answer to. We don’t know you and what you’re capable of. Some people can do the thing you’re asking about, others can’t. So just asking “can it be done” is a question that, if interpreted literally, has an easy answer that’s not very interesting or helpful (“yes, it can be done”), and if re-interpreted to mean what I think you really want to know (“can I , the specific person asking this question, do this thing?”), isn’t a question that I or anyone else here have the information to answer.
Perhaps the most helpful way of addressing the question is to look at the number of people who can do the thing you’re asking about. Well, I’ll be honest, that number is extremely small. Most people who want a career in academia already find it challenging enough to do one PhD in one discipline and then pursue a position as researchers in that one discipline. And even from among those super talented people who find it a bit easier than the rest and are smart and hardworking enough that they can realistically contemplate specializing in two very distant disciplines, one of which being as notoriously difficult as theoretical physics and being acquired purely through self-study, only a vanishingly small fraction of that already small group will care to invest the time and energy that it would take to broaden their reach in such a way. For those people it’s not really about a lack of ability - more about the fact that it’s an inefficient strategy for becoming successful and maximally realizing one’s potential; but it kind of amounts to the same thing in the end.
Summary: can it be done? Yes. Is it something that I’d recommend to anyone to have as their career plan? No.