I'm reading about quantum circuits.
I've just read about CNOT gate and after that, I read about the controlled U gate.
Can someone please clarify what is the difference between the two circuits below? The first one is the controlled-Hadamard gate (c-H). But what is the second one?! What is the difference between the matrix of the second and the first?
What I'm guessing is that the first one is going to be controlled by the first compound qubit, and the second by the second compound qubit, is that right?!