Let ∣Ψ⟩|\Psi\rangle∣Ψ⟩ be a ground state in a two-dimensional topological phase, let AAA be a spatial subsystem, and let ρA=TrAˉ∣Ψ⟩⟨Ψ∣\rho_A=\operatorname{Tr}_{\bar A}|\Psi\rangle\langle\Psi|ρA=TrAˉ∣Ψ⟩⟨Ψ∣ be…
