I am trying to calculate mutual entropies using QuTiP, but I am being unsuccessful so far. More specifically, I consider a 2^n x 2^n matrix representing the density operator of a n-qubit bipartite system AB made of system A (first m < n qubits) and B (remaining n-m qubits). No tutorial nor material on the internet addressed this specific task.
For simplicity, let us consider a 1-qubit system A and a 2-qubit system B and a density operator of dimension 8x8 representing AB in computational basis.
More practically in python, let
rhoAB = Qobj=(np.random.rand(8,8)), and assume that this is a valid density operator.
How should I call entropy_mutual so that I can get this measure between A and B, in particular, regarding the arguments selA and selB? Ideally, I would call something like
entopy_mutual(rhoAB, selA=, selB=[2,3]) but this not the approach how the function interprets the subsystems and their respective dimensions.