I have recently finished my master's thesis and I want to start applying for PhDs soon. Considering that I did my PhD in subject A would it be considered 'normal' to apply for PhDs in subject B? I feel that not doing your master's thesis in subject B would set you back in the sense that you would miss out on quite a bit of hands on experience in that subject. How much are you expected to learn while doing the PhD and how much is expected as prerequisite knowledge?
I did my master's in Theoretical Physics if that's relevant and subject A = simulations in soft condensed matter and subject B = quantum computing (but maybe other subjects still)