Quantum Annealing — Adiabatic Gap & Schedule

Transverse-field Ising model: energy spectrum, gap closing, annealing schedules

Model Parameters

0=Linear, 1=Quadratic, 2=Roland-Cerf

Spectral Analysis

Ground energy E₀--
First excited E₁--
Gap Δ(s)--
Min gap (s*)--
QA runtime T*--
Adiabatic theorem: T* ∝ 1/Δ_min²
H(s) = -(1-s)Σσˣᵢ - s(JΣσᶻᵢσᶻᵢ₊₁ + hΣσᶻᵢ)
Gap closes at phase transition → exponential runtime
Roland-Cerf schedule: optimal for Grover (polynomial gap)