4 ms·
I was a bit bugged by the section about the density matrix. He writes: > Then you compute the outer product of the vector with itself I'm not sure what he mea
by grondilu 12y ago
I was a bit bugged by the section about the density matrix. He writes:
> Then you compute the outer product of the vector with itself
I'm not sure what he means by outer product here. Isn't the outer product of a vector by itself always nul?
- nshepperd 12y agoThe outer product of vectors `u, v` is the matrix `A_ij = u_i · v_j`. That is, a matrix containing the product of each component of u with each component of v. You may have been thinking of the cross product.
- tagrun 12y agoIt's just the Kronecker product or tensor product: (vector)⊗(Hermitian conjugate of the vector). It's not null unless the vector itself is null.