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2 votes

Time for ferromagnet to align with magnetic field

Well, a bunch of factors come into play. First, you've got the material itself. Different ferromagnetic materials have different properties that affect how quickly their magnetic moments can rearrange ...
Testina's user avatar
  • 87
0 votes

Sublattice Magnetization of Heisenberg Model on triangular lattice

Why does no SSB in finite systems imply we have to look at $\hat m_z^2$ instead of $\hat m_z$? This is a common point to get confused about SSB. To really understand it, you would actually need to ...
Jun_Gitef17's user avatar
0 votes

One-dimensional $q$-state Potts Model Partition Function - without Boundary Conditions

You can also solve this using a substitution: We start again with the Hamiltonian $$ H(\vec s)=- J \sum_{i=1}^{N-1} \delta(s_i - s_{i+1}) $$ where $s_i \in \mathbb S$ are entries of the global ...
Noel Schwabenland's user avatar
1 vote

Diagonalizing the all-to-all quantum spin model (quantum Curie-Weiss) with uniform couplings

Assuming that each spin has total spin $s$, then you can rewrite the Hamiltonian: $$ H = -\frac J2\hat S{}^2 +\frac {JN}2s(s+1)\\ \hat S = \sum_i \hat s_i $$ You therefore just need to diagonalize $\...
LPZ's user avatar
  • 10.9k
1 vote

Hamiltonians with collective quantum spins and their ground states

I don't know any relevant references. And I'm not sure that the statement about the ground state is always true. But I want to offer some thoughts about when and why this statement might be true. ...
Gec's user avatar
  • 5,232
0 votes

Product of Majorana operators after a orthogonal transformation

Yes! We can work it out for a general matrix $M$ that preserves the commutation relations of the Majorana operators (which are the orthogonal matrices). $$\gamma_k \mapsto \sum_l M_{kl} \gamma_l $$ ...
Nandagopal Manoj's user avatar

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