Recent content by Jomenvisst

I suspect the confusion arises when thinking of a many electron system, that is properly described only by a many body wavefunction, in terms of single electrons interacting, in some sense, as classical particles. I think a helpful concept if you still want to pursue that line is that of the...

Thank you for the answer. I agree with that, but that doesn't necessarily mean that <V>(t) != (1/2) <E>. I still feel the equality should hold.

So, this has been bothering me for a while. Lets say we have the wavefunction of a harmonic oscillator as a general superposition of energy eigenstates: \Psi = \sum c_{n} \psi _{n} exp(i(E_{n}-E_{m})t/h) Is it true in this case that <V> =(1/2) <E> . I tried calculating this but i...

didnt think throguh your 4), but this is what you can do once you get to 3): Ax= 0 => (Ax)'Ax = (Ax|Ax) = ||Ax||^2 = 0 <=> Ax = 0 where (,|,) denotes the scalar product and ||.|| is the norm induced by the scalar product ( ||u|| = sqrt(u|u) ).

Ok, things seem a lot clearer now after this and after i did some exercises. Thanks a lot. In the basis { |\alpha z > , | β z >} the matrix representation of S_x is: Sx= ( \hbar /2 ) σx. ( Pauli matrix) Which has the eigenvalues +- ( \hbar /2 ). |βz> is the eigenvector corresponding to...

Right, so that makes sense then. Thank you. So the choice of expressing an arbitrary spinor as a linear combination of the projections of spin up and down on the Z axis is just by convention? Now, this also confuses me a bit, say i want to express the projection of the spin down angular...

I'm currently taking a first course in quantum mechanics and we just recently introduced generalized angular momentum. Now, take the special case of a spin-1/2 particle. If i understood this correctly there are two possibilities spin up: ms = 1/2 , and spin down ms = -1/2 , this comes from...