All Questions
Tagged with spin-chains quantum-field-theory
12
questions
1
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1
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36
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Why is the excitation energy of antiferro 1/2 spin XXZ chain associated with the $\psi_{n+2}$ and $\psi_{n-2}$
I do not understand the equation on page 5 of nagaoso's book "quantum field theory in strongly correlated electronic systems".
The Hamiltonian is shown in this form
$H=\frac{J_\bot}{2}\sum_{...
- 11
3
votes
1
answer
100
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Time reversal symmetry and Bosonization
Bosonization of Spin 1/2s to fields $\phi(x)$, $\theta(x)$ is defined as (Ref: 'Quantum Physics in 1-D' by Giamarchi):
$S^z(x)=\frac{-1}{\pi}\nabla\phi(x)+\frac{(-1)^x}{\pi a}\cos 2\phi(x)$,
$S^x(x)=\...
- 358
2
votes
0
answers
53
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"Entropy" of a set of correlators in a quantum system
Please forgive the ill-posedness of this question; I am hoping someone can help me formulate what I am asking more clearly.
Consider the ground state of a one-dimensional quantum spin chain on $N$ ...
- 472
1
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0
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216
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Magnons and creation and annihilation operators
I am trying to obtain the spin waves (or magnons) arising from a 1D Heisenberg spin-chain, namely
\begin{equation}
{\cal H}=-J\sum_{i=1}^N \mathbf{S}_i\cdot \mathbf{S}_{i+1}
\end{equation}
After ...
- 137
1
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0
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165
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Where to find a Path Integral treatment of 1D Quantum Heisenberg model or Quantum Spin Chain?
All:
Where to find a Path Integral treatment of 1D Quantum Heisenberg model or Quantum Spin Chain?
I would like to find a detailed calculation of path amplitude in such situation. I did some google ...
1
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0
answers
223
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How to find groundstate energy of a simple Hamiltonian at $N/L$-filling using Jordan-Wigner (JW) transformation?
$\underline{\textbf{Model:}}$
Let we have the $t-V$ model for spinless fermions on a 1D lattice, which is defined in second quantization operators as follows:
$$H_1 = -t\sum_i \big(c_i^\dagger c_{i+...
- 1,335
2
votes
1
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245
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Integrability of generalized Richardson-Hubbard model
Recently I got a bit interested in the possibility of finding spectrum of few interesting class of lattice quantum mechanical hamiltonians like Richardson's pairing hamiltonian, 1D Hubbard hamiltonian,...
- 1,108
8
votes
0
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618
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Mermin-Wagner and Heisenberg spin chains
The Hamiltonian for the spin 1/2 ferromagnetic Heisenberg spin chain is $H=-J\sum_i \vec \sigma_i \cdot \vec\sigma_{i+1}$ with $J>0$ and $\vec\sigma_i$ the Pauli matrices acting on ith lattice site....
- 8,815
1
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0
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153
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Boundary critical exponents of the 1D quantum XY model
Critical properties of the two-dimensional Ising model in the bulk and at the boundary are characterized by different critical exponent, see Ising model: exact results and McCoy: The boundary Ising ...
- 5,697
0
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0
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93
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At most $N$ gapless charge/spin modes in a system of $N$ coupled 1D chains?
Leon Balents and Matthew P. A. Fisher claimed the following without any further explanation ($N$ is the number of chains)
For a system of $N$ coupled 1D chains, the number of gapless charge modes ...
- 3,701
29
votes
2
answers
1k
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$\phi^4$ theory kinks as fermions?
In 1+1 dimensions there is duality between models of fermions and bosons called bosonization (or fermionization). For instance the sine-Gordon theory $$\mathcal{L}= \frac{1}{2}\partial_\mu \phi \...
- 8,815
11
votes
1
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1k
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Dual conformal symmetry and spin networks in ABJM
In this question, I would love to hear some independent opinions on an issue I asked Juan Maldacena, Nathan Berkovits, Dan Jafferis, and others, but all the physicists may be missing something. The ...
- 180k