Luckily for me (or unluckily for me), Iv'e narrowed my topics to specalise in to: Quantum Cosmology in theoretical physics and Quantum Chaos but from the number theoretic approach, i.e pure maths. So the problem is how to combine these two narrowed specialities?, I think I have also narrowed down two possible academic supervisors (one from the physics department and one from the maths department). Now I have a few questions: 1. Does it matter if I do my dissertation in the physics department or the maths departement? 2. Should it matter that if I were to write the dissertation in one department over the other, that the other advisor is not from this deparment? 3. One thing that bothers me is that, I am thinking of applying this year to two MSC programmes in my school (physics and maths) and after I were to finish 2/3 of my obligatory studies in each of them, if I were to continue to a PhD in one departement over the other, how would I inform each of my advisors of the other, it seems like a hassle to go between the two advisors back and forth? Any other tips on this matter are more than welcomed.