QUANTUM PHASE TRANSITION

Transverse-field Ising model — quantum criticality at J/h = 1

CONTROL PARAMETER

FERROMAGNETIC

OBSERVABLES

Magnetization ⟨σˣ⟩:
Ground energy E₀:
Energy gap Δ:
Entanglement S:
Correlation ⟨σᵢσⱼ⟩:

PHYSICS

H = −J∑σᵢᶻσⱼᶻ − h∑σᵢˣ

Critical point: J/h = 1
Universality: d=1 Ising CFT
Central charge c = 1/2
ν = 1, β = 1/8 (exponents)