- #1
Noora Alameri
- 12
- 0
Hey,
I am studying Spin 1/2 system, the case of 2 electrons in a magnetic field, since we have 2 electrons, we expect that the matrix will be of the size 4x4, which is what I have got.
As I know that I could use the density matrix to calculate the expectation values of any physical quantity such us <Sz> , <Sx> and <Sy> by taking the trace of the product of the density matrix with the one we want to find out.
but the point that disappointed me is that Sz operator for example is 2x2 matrix , and the density matrix is 4x4 ! I can't take a product of two matrices !
What is the best way to proceed ?
I am really struggling with this, I hope someone would help ()
Thank you
I am studying Spin 1/2 system, the case of 2 electrons in a magnetic field, since we have 2 electrons, we expect that the matrix will be of the size 4x4, which is what I have got.
As I know that I could use the density matrix to calculate the expectation values of any physical quantity such us <Sz> , <Sx> and <Sy> by taking the trace of the product of the density matrix with the one we want to find out.
but the point that disappointed me is that Sz operator for example is 2x2 matrix , and the density matrix is 4x4 ! I can't take a product of two matrices !
What is the best way to proceed ?
I am really struggling with this, I hope someone would help ()
Thank you