All Questions
3
questions
4
votes
0
answers
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Operator inequality between the Heisenberg Hamiltonian and the total spin
Consider a collection of $N$ spin-1/2 particles (qubits) with total spin
$$\vec{S} = \frac{1}{2}\sum_{n=1}^N \vec{\sigma}_n$$
and a Heisenberg Hamiltonian
$$H = -J \sum_{\langle n,m\rangle} \vec{\...
- 3,684
1
vote
0
answers
795
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Calculating expected values $\langle S_x \rangle$ and $\langle S_y \rangle$ in the Heisenberg model
Let's say, that we are considering the basic Heisenberg model with only two spin-particles. So our Hamiltonian can be written as follows:
$$
H = \sum_{\langle i,i' \rangle} S^{(x)}_i S^{(x)}_{i'} + S^...
- 409
2
votes
1
answer
2k
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Two spin-1 system and the projector onto total spin 2 subspace [closed]
I am having trouble grasping the projection operators in the context of composite spins system, e.g. with two spin-1. First off, a projector $P$ is said to be an operator that squares to itself, $P^2=...
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