Hello, I don't know what I am doing wrong but I have an additional i. The R matrix indeed flip the bit but also add a i coefficient.
If someone have an explanation thanks.
Hi,
Its correct. The i in front is a global phase (a complex number of unit norm) and global phases are not observable. So the final state is physically equivalent to the state without the i.
Careful though: only global phases in front of a whole state dont count. Relative phases in sums of states do count! (They are observable through interference phenomena).
Hope this clarifies.
NM
