Noise Models

Noise studies use PennyLane mixed-state simulation to evaluate robustness under consistent channels across supported workflows.

(1)\[\mathcal{E}(\rho) = (1-p)\rho + \frac{p}{3} (X\rho X + Y\rho Y + Z\rho Z)\]

The depolarizing channel in (1) is used as an isotropic benchmark noise model.

Noise channels implemented via PennyLane mixed-state simulation.

Supported channels:

  • depolarizing noise

  • amplitude damping

Noise placement:

  • applied between circuit operations

  • consistent across VQE, QPE, and evaluation stages


Depolarizing channel

\[ \mathcal{E}(\rho) = (1-p)\rho + \frac{p}{3} (X\rho X + Y\rho Y + Z\rho Z) \]

Produces isotropic decoherence.


Amplitude damping

\[\begin{split} E_0 = \begin{pmatrix} 1 & 0 \\ 0 & \sqrt{1-p} \end{pmatrix} \quad E_1 = \begin{pmatrix} 0 & \sqrt{p} \\ 0 & 0 \end{pmatrix} \end{split}\]

Models relaxation toward ground state.


Typical evaluation metrics

Noise studies examine:

  • energy deviation

  • convergence stability

  • excitation ordering robustness

  • optimizer sensitivity