XXZ Chain
Purpose and Hamiltonian
The XXZ chain is the $J_x=J_y$ specialization of the anisotropic Heisenberg chain:
$$ H=J\sum_i(X_iX_{i+1}+Y_iY_{i+1}+\Delta Z_iZ_{i+1}) +g\sum_iZ_i. $$
It is useful for anisotropy, magnetization, gap, and conserved-$S^z$ benchmarks.
Basis and use
The dense computational-basis matrix has dimension $2^N$.
from quantum_lattice_models import xxz_chain
H = xxz_chain(n_sites=6, coupling=1.0, anisotropy=0.7)
Parameters
| Builder | Parameter | Type | Default | Constraint |
|---|---|---|---|---|
xxz_chain |
n_sites |
int |
4 |
>= 1 |
xxz_chain |
coupling |
float |
1.0 |
|
xxz_chain |
anisotropy |
float |
0.7 |
|
xxz_chain |
field |
float |
0.0 |
|
xxz_chain |
periodic |
bool |
False |
User notes
xxz_chain delegates to heisenberg_chain; its field term therefore has a
positive sign. Fixed-magnetization sectors are planned but not yet available.
Related: Heisenberg chain, XY chain.