0.050
0.08
E(θ) = —
E_exact = —
Step: 0
Δθ₁ = —
Δθ₂ = —
E_exact = —
Step: 0
Δθ₁ = —
Δθ₂ = —
VQE algorithm:
θ ← θ − η∇E(θ)
Gradient via parameter-shift rule:
∂E/∂θ = [E(θ+π/2) − E(θ−π/2)]/2
Advantage over exact diag: exponentially fewer parameters
θ ← θ − η∇E(θ)
Gradient via parameter-shift rule:
∂E/∂θ = [E(θ+π/2) − E(θ−π/2)]/2
Advantage over exact diag: exponentially fewer parameters