Topological Observables
Pump phase φ: –
Chern number C₁: +1
Pumped charge Q: –
Cycles: 0
Band gap: –
Thouless (1983): adiabatic charge pumped per cycle = Chern number C = ∮ Berry curvature dk dφ / 2π. Exactly quantized as long as gap remains open. SSH-like model: H(k,φ) = [t+δcos(φ)]σ_x + [δsin(φ) + V₁sin(k)]σ_y. Experimentally realized in cold atoms and photonic lattices.