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Questions tagged [ising-model]

The Ising model of ferromagnetism in statistical mechanics consists of discrete bimodal (+1 or −1) "spin" (moment) variables in a simple Hamiltonian interacting with their next neighbors on a lattice. The one-dimensional variant does not evince a phase transition, but the two-dimensional square-lattice one does. Use for analog and generalized discrete models on several lattices and dimensions.

1 vote
1 answer
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I have a very basic confusion about the 2D random-bond Ising model on a square lattice with Boltzmann weight $$\omega(J_{ij},\sigma_j)=\prod_{ij}(1-p)^{\delta_{J_{ij}=1}} p^{\delta_{J_{ij}=-1}} e^{-\...
Andi Bauer's user avatar
4 votes
1 answer
137 views

I'm working through Chapter 14 of Mezard and Montanari's Information,Physics,and Computation ("Belief Propagation"). I'm stuck on Exercise 14.10 in Section 14.4 about the 2d Ising model. In ...
gms5998's user avatar
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9 votes
1 answer
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When reading about phase transitions, one quickly encounters the Ising model and its variants (spin glass, Potts, etc.). This model is used to explain ferromagnetism in a very satisfying way. It is ...
Weier's user avatar
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2 votes
0 answers
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I'm totally new to tensor networks, and I'm currently learning on my own from papers, tutorials, and videos. Right now, I'm trying to understand how to construct a Matrix Product Operator (MPO) for a ...
MuZo's user avatar
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2 votes
0 answers
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I’m working on exercise 11.6 (a) in Conformal Field Theory by Di Francesco, Mathieu & Sénéchal (the “yellow book”). The problem defines the parity operation as $$ P:\qquad \psi(z)\longrightarrow\...
baba26's user avatar
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1 vote
1 answer
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Introduction I'm studying the Ising Model described by the partition function: $$ Z = \sum_{\{s_{i}\}} \exp \bigg\{ \dfrac{1}{2} \, \vec{s} \, \mathbf{J} \, \vec{s}^{\,\scriptscriptstyle T} \bigg\} ...
akkar's user avatar
  • 13
2 votes
1 answer
129 views

Not a physicist, apologies in case I lack rigor. Consider the following Hamiltonian: $$H=\sum_j \gamma_j\sigma^z_j\sigma^z_{j+1} + h\sum_j \sigma^x_j.$$ I am looking for a lower-bound to the spectral ...
Daniele Cuomo's user avatar
3 votes
0 answers
113 views

I am asking about the infinitely long layered Ising model with a finite number of layers. The model is assumed to be invariant under translations along the direction in which it is infinite. All ...
Gec's user avatar
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1 vote
0 answers
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Does Jordan-Wigner transformation produce the eigenvectors of Ising model? My understanding of diagonalisation for quantum mechanics is that it can help you calculate the propagator of a Hamiltonian ...
Luca's user avatar
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1 vote
0 answers
245 views

The Wikipedia page on the critical exponents of the Ising model presents the following table: This page lists the critical exponents ($\alpha$, $\beta$, $\gamma$, ...) and their values for some ...
Foxy's user avatar
  • 185
7 votes
2 answers
392 views

The susceptibility is defined by $\chi = \partial M/ \partial H$ and for a ferromagnet above the critical temperature $T_C$, it is given by the Curie--Weiss law, $\chi \propto (T-T_C)^{-1}$. What ...
FusRoDah's user avatar
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2 votes
0 answers
118 views

There is quite a lot of discussion on SE about correlation functions in lattice models. So I would say that it is well known that the two-spin (two-point) correlation function has the following ...
Gec's user avatar
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5 votes
0 answers
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I'm not versed at all in high energy physics, I come from a statistical mechanics background, hence, all of what follow is far from my comfort zone. I will also talk about what is, I believe, the lore ...
Syrocco's user avatar
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2 votes
1 answer
159 views

Consider the Ising model in $d$ dimensions with a random local magnetic field $H_i$: $$ \mathcal{H} = -\frac{J}{2} \sum_{\langle i, j \rangle} S_i S_j - \sum_i H_i S_i $$ where $\langle i, j \rangle$ ...
TheFox's user avatar
  • 77
0 votes
1 answer
135 views

I'm reading this article which shows the breakdown of the Mermin-Wagner theorem for a 2D system with finite size. In short, the Mermin-Wagner theorem states that no system with dimensionality d $\leq2$...
samuelmsoares's user avatar

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