XXZ Heisenberg Spin Chain
H = Σ [SˣSˣ + SʸSʸ + Δ·SᶻSᶻ] — three quantum phases in one parameter
Phase: XY
⟨Sz⟩ = 0.00
⟨SzSz⟩ = 0.00
⟨Sx⟩ = 0.00
The XXZ chain has exact Bethe ansatz solution. Δ < −1: ferromagnetic (all spins aligned); −1 < Δ < 1: gapless XY phase (power-law correlations, Luttinger liquid); Δ > 1: gapped Néel antiferromagnet.
Click the phase diagram to set Δ. Monte Carlo updates spins via Glauber-like dynamics.