Of course the traditional answer to this question would be to do a Ph.D. in physics. If that isn't an option there are usually more specialized books in specif

Of course the traditional answer to this question would be to do a Ph.D. in physics. If that isn't an option there are usually more specialized books in specific research areas beyond the level of undergrad/beginning grad-level texts. For example if you search for "quantum dots" on Amazon you will get a number of hits. That said a significant part of learning a field of research is becoming familiar with the primary literature of that field (ie. published papers). In fact if you were in a Ph.D program you would probably also have to spend quite a lot of time and effort reading papers to get up to speed. If you encounter an equation you don't understand there is undoubtedly some paper where it was first introduced. If it's widely used there may also be review papers which attempt to give a broader understanding of that equation in context. Usually finding these is a matter of doing a literature search (Google Scholar is quite useful for this) and tracing references in papers once you've found them. Have you tried asking your contacts to recommend a list of books and key papers in their field ?