Questions tagged [heisenberg-model]

For questions related to the Heisenberg model Hamiltonian.

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8
votes
1answer
65 views

What's the most efficient way to obtain the ground state of spin models exactly?

(Note: an earlier version of this question had been asked on Phys.SE before) It is known that finding the ground state of classical spin glasses is NP-hard: it will take (at least) an exponential ...
13
votes
3answers
201 views

Are there any codes to study magnetic materials?

I have used a few codes for studying magnetic materials (specifically core-shell nanoparticles with an AFM shell and an FM core). These are: Vampire: For the calculation of curie temperature via ...
11
votes
0answers
86 views

How to choose the values of J and spin parameters in a heterogeneous spin system?

In this work, graphene-based systems that are described by mixed spin-3/2 and spin-5/2 are studied using the ising-model. A diagram of the structure is shown bellow: The Hamiltonian used is: \begin{...
18
votes
2answers
436 views

What are good random number generators for Monte Carlo calculations?

Many problems in Computational Physics need the use of random number generators. When studying magnetic materials using the Heisenberg/Ising Hamiltonians (related questions about them can be seen here,...
7
votes
1answer
101 views

What measured quantity can be associated to the value of the J parameter in the Heisenberg/Ising hamiltonians?

This question is related to other one here in the MatterModelingSE: Is it possible to calculate/estimate the value of the J parameter to be used in the Heisenberg/Ising hamiltonians? Here J is the ...
6
votes
1answer
137 views

Is it possible to calculate/estimate the value of the J parameter to be used in the Heisenberg/Ising Hamiltonians?

Studying magnetic systems, two frequently used approximations are the Heisenberg and Ising models (a discussion about these approximations can be read here): \begin{equation} \tag{Heisenberg} \hat{H}...
13
votes
1answer
339 views

Is Heisenberg model or in its simplier form Ising model a good approximation to study magnetic systems?

Heisenberg model $$\hat{H}=-\sum_{\langle i j\rangle}J\hat{S}_i\hat{S}_j$$ And in its simplified version, the Ising model $$\hat{H}=-\sum_{\langle ij\rangle}J\hat{S}_i^z\hat{S}_j^z$$ are widely ...
24
votes
3answers
255 views

What are examples of materials that closely correspond to the Heisenberg model?

I use the antiferromagnetic Heisenberg model all the time: $ H = J \sum \limits_{\langle i,j \rangle} \vec S_i \cdot \vec S_j$ What are some examples of materials that are well-described by this ...