According to my understanding of QC/QM:
- A matrix is a function/operation which when applied on vectors, changes/rotates them.
- Ket and bra notation is used to denote quantum state.
Question 1:
<0|0> gives scalar
when bra zero and ket zero are multiplied we get a scalar. I understood this numerically but what exactly is this scalar? what does it represent?
Question 2: |0><0| gives matrix
when ket zero and bra zero is multiplied we get a matrix, I understood it numerically but what exactly this matrix represent?
Bonus Question:
since bra and ket represent quantum states so multiplying two quantum states give a scalar or matrix. what does it mean to multiply quantum states? why do we multiply quantum states? Like multiplying a scalar with vector SCALES the vector, here role of multiplication is easy to get.