All Questions
Tagged with spin-models spin-chains
66
questions
1
vote
0
answers
59
views
Discrepancy regarding Husimi Probability distribution calculation
I am trying to simulate a system of j qubits and for visualization of the dynamics considering the Husimi distribution of the state.
To carry out the projection onto coherent states I have proceeded ...
- 41
2
votes
1
answer
245
views
Integrability of generalized Richardson-Hubbard model
Recently I got a bit interested in the possibility of finding spectrum of few interesting class of lattice quantum mechanical hamiltonians like Richardson's pairing hamiltonian, 1D Hubbard hamiltonian,...
- 1,108
2
votes
1
answer
178
views
Reduced density matrix of the edge spin-1/2 in AKLT spin chain
I am trying to understand the paper titled, "Entanglement in a Valence-Bond-Solid State" by Fan, Korepin, and Roychowdhury (https://arxiv.org/abs/quant-ph/0406067).
I was able to understand the ...
- 41
1
vote
1
answer
668
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About spin chain string order
We know that the string order of a spin chain is defined as
$$\mathcal{O}^\alpha=\lim_{i-j\to\infty}\left\langle S_i^\alpha\prod_{k=i+1}^{j-1}\exp(i\pi S_k^\alpha)\ S_j^\alpha \right\rangle$$
now ...
- 1,097
2
votes
0
answers
124
views
Can we have a spin glass in the one-dimensional Heisenberg hamiltonian with nearest neighbours only?
Consider the one dimensional Heisenberg Hamiltonian of the form
\begin{equation}
H = - \sum_{<i,j>} J_{ij} \mathbf{S}_i \cdot \mathbf{S}_j
\end{equation}
with nearest neighbour interactions. ...
- 451
3
votes
0
answers
498
views
Transverse field Ising model with open boundary conditions
what is the energy dispersion of the transverse field Ising model looks like in the case of open boundary conditions?
In the case of periodic boundary, the energy takes the form of
and the ground ...
- 325
5
votes
1
answer
1k
views
R-matrix for spin chains
In algebraic Bethe ansatz procedure, one of the central objects is the R-matrix satisfying the Yang-Baxter equation, but all the papers/books give directly its expression without deriving it, so my ...
- 162
1
vote
0
answers
153
views
Boundary critical exponents of the 1D quantum XY model
Critical properties of the two-dimensional Ising model in the bulk and at the boundary are characterized by different critical exponent, see Ising model: exact results and McCoy: The boundary Ising ...
- 5,697
0
votes
0
answers
117
views
References or resource recommendation for mapping of 1D spinless Hubbard model into XXZ Heisenberg model
I read from somewhere that 1D spinless Hubbard model can be mapped onto XXZ Heisenberg model but I don't remember from where did I read this sentence. I tried googling it but couldn't find any thing ...
- 1,335
3
votes
1
answer
1k
views
Heisenberg ferromagnet in continuum limit
I consider the case of the simple, say 2D, Heisenberg ferromagnet with exchange interaction between the nearest neighbors. The Hamiltonian is:
$$H = -J \sum_{<ij>} \mathbf S_i \mathbf S_j,$$
...
- 43
3
votes
1
answer
510
views
ground state of spin chain with $Z_i X_{i+1} Z_{i+2}$ interaction
the problem comes from transverse field Ising model, with an extra 3-spin interaction term
$$H=H_0+H_1+H_2=-h\sum_{i=1}^{N}X_i -\lambda_1 \sum_{i=1}^{N-1}Z_i Z_{i+1}-\lambda_2 \sum_{i=1}^{N-2}Z_i X_{i+...
- 1,113
7
votes
1
answer
395
views
Kosterlitz-Thouless in the XXZ chain: instanton condensation?
The anisotropic spin-$\frac{1}{2}$ Heisenberg chain $$H = \sum_n S^x_n S^x_{n+1} + S^y_n S^y_{n+1} + \Delta S^z_n S^z_{n+1}$$ is known to have the same physics as the two-dimensional classical XY ...
- 9,081
0
votes
1
answer
494
views
Matrix form of the 1D quantum Ising model mapped to free fermion model via the Jordan -Wigner Transformation
The free fermion Hamiltonian for the 1D quantum Ising model is
$$H = -J\sum_i (c_{i}^{\dagger }c_{i+1} +c_{i+1}^{\dagger }c_{i}+c_{i}^{\dagger }c_{i+1}^{\dagger }+c_{i+1}c_{i}-2gc_{i}^{\dagger }c_{i} ...
- 56
1
vote
1
answer
154
views
Spin Chains - Why are eigenstates always expressed in the z-basis
I was wondering why when we have spin chain Hamiltonians, like the Heisenberg model, we always express the eigenstates in the spin z- eigenbasis.
Or maybe, I could pose my question this way - to be ...
- 56
2
votes
0
answers
50
views
Example of spin chains with finite-lifetime quasi-particles?
Does anyone know a one-dimensional spin model where the low-energy excitations have a finite lifetime? (E.g. in terms of the spectral function $\mathcal S(k, \omega)$ this means one would get a finite ...
- 9,081