Collecting coefficients of non-commutative products from an expression

Question

I am trying to manipulate a Hamiltonian with non-commutative operators, $a_j,a_j^\dagger$. After some algebra using NCAlgebra package in Mathematica, I have an expression like, $$H = C_1 (b**a) + C_2 (a**a^\dagger) + C_3 (d^\dagger d) + \cdots $$ How do I extract/collect coefficients like $C_1,C_2$? I have tried NCCollect[H, b**a], but it does not give me the desired answer $C_1$? I am new to this and appreciate any help. Thank you.

Answer 1

You can do this with NCCoefficientList as in:

H = C1 b ** a + C2 a ** aj[a] + C3 d ** aj[d]
NCCoefficientList[H, {a, aj[a], b, d, aj[d]}]

which returns

{C1, C2, C3}

Note that you have to add also aj[a] and aj[d] to the list of variables.