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Cost Landscape Explorer

Variational cost surface visualization

A 1-qubit variational circuit Ry(theta)Rz(phi)|0> is measured against different Hamiltonians. The full 2D cost surface is rendered as a heatmap. Click to place a parameter point, toggle the gradient vector and gradient field overlay, and locate the global minimum. This is the landscape your optimizer must navigate.

Pauli Z: ground state is |0>

C(theta,phi) = 1.00000|grad C| = 0.00000C_min = -1.00000
-1.0pi-0.6pi-0.3pi00.3pi0.6pi1.0piphi (Rz angle)-1.0pi-0.6pi-0.3pi00.3pi0.6pi1.0pitheta (Ry angle)1.00-1.00C

Click anywhere on the landscape to place the parameter point. The gold dot shows your position; purple arrow shows the negative gradient direction. Green crosshair marks the global minimum.

Cost Landscape Explorer — VQA Labs · hbar.university