[Feature] Time-dependent Hamevo with noise operators

[chMoussa]

Closes #622 . Adding the noise_operators argument to Hamevo as in Pyqtorch.

TODOs:

• Add a noise_operators argument to Hamevo
• Set the conversion to Pyqtorch appropriately (solver, steps, and noise_operators)
• Add/Fix tests
• Add docs

Note that one may need to adapt the NoiseHandler class later to set the noise_operators accordingly to the type of analog noise. However, this may require harmonising all noises in all backends. Thus this is left for future work.

[jpmoutinho]

Thanks @chMoussa. I think it would be more consistent to stick to qadence blocks when it comes to interfaces asking for operators.

[RolandMacDoland]

Hey @chMoussa thanks for this ! Unsure about how it works though. I thought you had to specify operators but instead you seem to be passing a list of identities ?

[chMoussa]

My main question would be in practice what do users typically use. If it's mainly pauli strings, then it would be much more convenient to do it with Qadence blocks. If they want to use arbitrary matrices, it could also be a use for the MatrixBlock, which has not been used that much.

@jpmoutinho @RolandMacDoland I modified eventually the code to work with a list of blocks as noise operators. We won't support certain cases such as parametric blocks but I left a warning note in docs about using MatrixBlock instead. This is reflected in the tests now. Let me know what you think of it.

[jpmoutinho]

Thanks @chMoussa, looking good. I think my main question now is about how general / restrictive should the noise model be. In Pulser only single-qubit jump operators are available. If we don't have that restriction, is that ok?

[jpmoutinho]

Thanks, final comment left on the docs but otherwise lgtm.