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21
votes
1answer
320 views

Fluctuations of an interface with hammock potential

This question is related to that one. I ask it here since comments are too short for the extended discussion that was going on there. I am interested in a very simple interface model. To each $x\in\...
1
vote
1answer
77 views

Find out ground sates for large 2D classical spin model

Reaching the ground state of a large 2D classical spin model (e.g. classical Heisenberg model) might be a relatively difficult task while using conventional "flip/reject" Monte Carlo method. The ...
0
votes
1answer
69 views

Why does a spinning nucleon generate a magnetic field?

I am trying to understand how NMR works, but I am not sure why a spinning nucleon produces a magnetic field. Is this a consequence of the quark structure inside?
7
votes
0answers
96 views

Do bipartite spin glasses have simple relaxation dynamics?

From what I gather, a Boltzmann machine (BM) is essentially a spin glass with no applied field evolving under Glauber dynamics (if this is at all mistaken, I don't think it will be off enough to ...
3
votes
0answers
101 views

Toric Code and the String-Net Model

What, exactly, makes the toric code a quantum error-correcting code as opposed to any other string-net model? What makes it special? The way I understand it, it's a normal string-net model on a torus, ...
2
votes
0answers
25 views

Chiral spin liquid flux states on the Kagome lattice

Short version: Is it possible to arrange the fluxes for the Kagomé lattice with triangle flux $\phi_\triangle=\frac{\pi}2$ and hexagon flux $\phi_{hex}=0$ using a single unit cell? Longer version: I ...
2
votes
0answers
125 views

Fermion 1D Hubbard Model ground state in the U = 0 limit

I am trying to determine the ground state of the 1D fermionic Hubbard model at half-filling of $2L$ sites with $L$ electrons with spin-$\uparrow$ and $L$ electrons with spin-$\downarrow$ in the $U=0$ ...
2
votes
0answers
61 views

Spin Transition Energies

I am reading a paper: http://arxiv.org/ftp/arxiv/papers/1305/1305.2445.pdf On p. 22, the following Hamiltonian is given: $$ H = \mu_B g \mathbf{B} \cdot \mathbf{S} + D(S_Z^2+\frac{1}{3}S(S+1)) + E(...
1
vote
0answers
76 views

Kitaev honeycomb model: Ground state degeneracy

Consider the Kitaev honeycomb model: $\quad -J_x\sum_{x\; links} S_i S_{i+x}- J_y\sum_{y\; links} S_i S_{i+y}- J_z\sum_{z\; links} S_i S_{i+z}$. From Lieb's theorem, the ground state is given by, $...
1
vote
0answers
111 views

Wen plaquette model with one kind of plaquette operator

Let us say that we modify the familiar Wen plaquette model so that only one kind of plaquette operator is in the Hamiltonian which is a product of $\sigma_z$s, what kind of topological order or state ...
1
vote
0answers
113 views

Ising model at high vs. low temperature

The output of the Ising model over a 2D binary lattice looks to have spin states uniformly distributed over the lattice for high values of the temperature parameter with the output attaining ...
1
vote
0answers
71 views

Topological S-matrix as an operator in the graphical calculus

My question comes from the following classic paper by Kitaev: Anyons in an exactly solved model and beyond (arXiv link) In Appendix E (pg 86), Kitaev introduces a diagram operator $S_z$ which acts ...
0
votes
0answers
62 views

Electron spinning speed and “matter” it is made from

I wonder how electron may have spin if its model has no space occupied solely by the electron. Is it possible to estimate this rotation speed knowing its mass, charge and magnetic field emerged? If ...
0
votes
0answers
24 views

The Hamiltonian of the Spin-Boson Model

I came across the following two specifications of the spin boson model with weak system-environment coupling: Dissipative/Population Decay Model: $$ \mathcal{H} = \frac{\omega_{0}}{2}\sigma_{z} + ...
0
votes
0answers
72 views

Gauge invariance of classical XY spin model

I am trying to understand gauge invariance as it is applied to a XY model Any ideas if it is in fact gauge invariant? Examples of how it is or isn't would be very helpful. If it is not gauge invariant,...
0
votes
0answers
62 views

What is the central charge of the disordered $q$-state Potts model, for large $q$?

The central charge of a model, is, heuristically related to the number of microscopic degrees of freedom. Is there a simple argument for the asymptotic behavior of the central charge for the ...
0
votes
0answers
156 views

A simple question on the projected wave function?

For example, consider a spin-1/2 AFM Heisenberg Hamiltonian $H=\sum_{<ij>}\mathbf{S}_i\cdot\mathbf{S}_j$, and we perform a Schwinger-fermion($\mathbf{S}_i=\frac{1}{2}f^\dagger_i\mathbf{\sigma}...
-1
votes
0answers
26 views

SU(2) Coherent State and Probabilities

The SU(2) Corherent State for a for more than 1 two level system is given by: $$ | \eta, J \rangle = (1 + |\eta|^2)^{-J} \sum_{m=-J}^{J} \sqrt{\binom{2J}{J + m}} \times \eta^{J + m} |J, m \rangle, ...