The experimental results demonstrate a significant lack of fidelity; here we examine what we believe to be the most likely sources of loss of fidelity, considering the state generation and detection separately before simulating the experiment as a whole. The product operator calculations in Sections 2 and 11 were performed assuming ideal pulses, during which precession about the static Hamiltonian is neglected. A more general approach is to consider that the static Hamiltonian is always acting on the spin system, effectively tilting the axis of nutation during pulses out of the 𝑥𝑦-plane. . It is not convenient to model this effect within the product operator formalism as the static and driving Hamiltonians do not commute, and so we turn to numerical simulations to describe the evolution of the quantum state. Further details of the simulations are included in Section 12.