I am newly learning quantum computing and am confused about some concepts. Suppose your qbit is the electron of a hydrogen atom and its in the state α|0> + β|1> . As far as I can understand, this means that if you measure the qbit in |0>, |1> basis, you will get a ground state electron with the probability |α|2 and an exited one with the probability |β|2. So what does it mean when you say you are measuring the state in some other basis? say |+>, |-> basis. How do you physically do this? Thanks.