356 views

Tensor product postulate [duplicate]

Non relativistic quantum mechanics assumes that a composite system should be described with the tensor product of the component systems. This is the tensor product postulate of quantum mechanics. I ...
464 views

Why tensor product? [duplicate]

Let $A$ an $B$ be two discrete observables (like spins). When exactly and why we have to consider their tensor product when talking about the mutual observation of the corresponding phenomena?
164 views

Quantum spin, tensor product: a long time relationship [duplicate]

Anyone who has studied quantum mechanics know the following relation: $2 \otimes 2 = 3 \oplus 1$ But how did a man woke up and said "Hell yeah, I'll use tensor product of two spin $1/2$ to simulate ...
114 views

Why are systems joined via a tensor product? [duplicate]

This question comes from seeing that the triangle addition rule for quantum mechanics comes out of groups/representation theory; I thought this was odd as we haven't used any group ideas in QM up to ...
23 views

748 views

Indistinguishability in Quantum Mechanics

When describing the defining characteristics of bosons and fermions, I have a problem with the idea of "label switching" - whereby you have the wavefunction for two particles and the particles' labels ...
691 views

Tensor product states in QM

In QM, we use tensor products to construct the vector space of the states of a multi-particle system - but that construction doesn’t seem to have a counterpart in classical mechanics. In QM, it seems ...
A three-dimensional volume $V$ contains a certain number $N$ of electrons and they can't escape the volume $V$. Assume for simplicity that the potential $\mathcal{V}(\mathbf{r})$ is zero in all the ...