I am a PhD student in physics at a US university. I am currently in my third year and I do not feel that my research interests are perfectly aligned with that of the group. Besides a mismatch of research interests, the advisor (PI) is a senior person and it seems difficult for me to interact with him directly aside from a 2 min talk during the group online meeting each week.
Now, there are several people in the department that I like their research better. However, I do not actually know how to approach the situation, since I actually don’t know if they are willing to take me as a PhD student. Let’s suppose two possible scenarios:
A) I go talk first to the other professors and see if they’re interested in working with me. In that case, I have a feeling that I’m doing this behind the back of my advisor. Also, they will ask me which group I’m in, so I’m not sure what they will think when I tell them that I’m currently in professor X group
B) Talk to my advisor first, but then I would be very worried about what will happen if the other professors whose work is interesting to me are unwilling to take me as a PhD student.
Which one of these options should one take?
I also have this question: if I’m working in a certain group, can I just study whatever I find interesting in the subject, then contact and collaborate with other professors in the department not in my group? More precisely, if my group is interested in a subject X, but there's a nearby subject Y that I find much more interesting. Can I just work on Y in parallel and contact other people in the department working on Y?