Kitaev Honeycomb Spin Liquid

Exactly solvable quantum spin liquid with Majorana fermions and anyonic excitations

Coupling Constants

Phase: B (Gapless)

Flux Sector

x-bond (σxσx)
y-bond (σyσy)
z-bond (σzσz)
Vison (flux)
In each plaquette, Z₂ flux Wp = ∏σ = ±1. Visons are static Z₂ gauge excitations; Majorana fermions hop in the background flux. In phase B+κ, non-Abelian anyons appear at vison cores.

Phase Diagram

Phase A (gapped): one coupling dominates (|Jα| > |Jβ|+|Jγ|). Abelian anyons. Z₂ topological order.

Phase B (gapless): triangle inequality satisfied. Dirac-like Majorana fermions. With κ≠0 → gapped non-Abelian phase (Ising universality).

Gap: Δ ∝ κ·|Jx Jy Jz|/J²