Hello I am currently looking for PhD's in physics just now but more specifically a project which uses my favourite topic of quantum theory. Up until now i have only thought about picking projects based on this preference but i would like to know what you learn on the PhD. So for example if i picked a project on based on imaging using quantum techniques would I only learn about quantum optics theory for 3-4 years and thats it? Because my interest expands to quantum optics, information, mechanics etc. I would like to learn about other topics in quantum as well. Does that also mean if i got a PhD in this area and i wanted to be an academic i could only do research in quantum optics? Because it seems very confined. I would like to learn about other topics in quantum as well in more detail. Can anyone with more experience elaborate on what the PhD process involves in terms of the learning aspects?