Entanglement entropy at quantum critical points: Can you ... - INFN

Away from Quantum Criticality: Topological Phases
• Topological Phases are proximate to conformal quantum critical points and
can be accessed by relevant perturbations
• Topological Phases have a finite correlation length ξ.
S = c′
3 log ξ a + . . . for ξ ≫ a
• For a < ξ < ∞, the entropy is defined by a crossover scaling function
whose behavior is controlled by the correlation length ξ
• At the stable fixed point, ξ → a
S = s 0
L
a − γ
γ is universal (Kitaev and Preskill (2006); Levin and Wen (2006).)
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