I am trying to create the following circuit in IBM Quantum Composer but I cannot add the last H gate correctly. It falls in the wrong place. Why?
1 Answer
They are equivalent in the sense that they implement the same unitary.
But if you want to keep the alignment you can insert a barrier:
Note however that if you plan to run your circuits on actual quantum computer, in general barriers may affect the process of transpilation and execution. See here for details.
Update
In the new version of IBM Quantum Composer (now in beta) you can use freeform alignment to place gates anywhere in the composer: