Hi,

I am currently following this tutorial here https://pennylane.ai/qml/demos/tutorial_quantum_metrology.html, but replacing the phase_damp operations with the qutip simulation using mesolve for research purpose, then use the output density matrix from qutip to calculate the probabilities on each wire using projective POVMs (like |0\rangle \langle 0|) following the last parameterization. Unfortunately, it seems like doing this will prevent the autograd from calculating the gradient, thus no update for the parameters. A work around I have been tinkering with is trying to directly feed the mesolve output to pennylane’s quantum circuits again, which seems somewhat infeasible due to certain restrictions?

Thank you for any help!