Error in calculating the two-time correlation functions for time-dependent Hamiltonian

[Parvendra Kumar]

Dear Group Members,

I am facing a problem while calculating the two-time correlation functions for a time-dependent Hamiltonian with QuTiP 5. The code is working perfectly fine with version 4. 

However, with version 5, it shows: ValueError: tlist must be the same len as the array to interpolate

Please suggest how I can correct my code to make it compatible with QuTiP ver. 5.

Thank you in advance.

Regards,

Parvendra

[Éric Giguère]

You will need to build the time-dependent operators before passing them to correlation:

H = QobjEvo(H, args=args, tlist=tlist)

c_ops = [QobjEvo(op, args=args, tlist=tlist) for op in c_ops]

This tlist can be different than the one passed to correlation. 

Usually, it should span at least from tlist[0] + taulist[0] to tlist[-1] + taulist[-1], and since spline approximation are less precise closes to the edges, it could start a little before and end a little after these values.

But since you are using pulse, it's probably fine to have it defined only around them.

ps. For pulse, settings the max_step options is recommended: options={"max_step"=half pulse width}

Eric

[Parvendra Kumar]

Thanks a lot. 

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