TOPOLOGICAL ORDER

Toric Code · Anyons · Ground State Degeneracy

MODEL

LATTICE

OBSERVABLES

Genus g1 (torus)
GSD4 = 2^(2g)
Anyons present0
Wilson loop Z₁+1
Wilson loop Z₂+1

PHYSICS

H = -J_e Σ_v A_v - J_m Σ_p B_p
Toric code on torus has GSD=4 states, locally indistinguishable. Anyons (e-particles and m-vortices) are created in pairs. Braiding e around m gives phase -1 (mutual statistics). Cannot be deconfined by local perturbations — topological protection.