Topological Insulators
SSH chain — winding number, edge states, adiabatic pumping
v (intracell):
0.30
w (intercell):
0.70
N cells:
20
Animate Pump
SSH (Su-Schrieffer-Heeger) model: H = Σ v c†_{A,n}c_{B,n} + w c†_{A,n+1}c_{B,n} + h.c. Winding number W=1 when w>v (topological phase) → protected edge states at E=0. W=0 when w<v (trivial). Gap closes at v=w (topological phase transition).