This can then be converted to one of the maximally entangled Bell states by single qubit rotation operations (for example the |𝜓 ; ⟩⟨𝜓 ; | density matrix can be generated by applying 90° pulses along +𝑦 to spin S and -𝑦 to spin I), and so a DFHE with an appropriately selected inter-pulse delay represents an entangling gate. However, if the initial state is not pure the result of the DFHE experiment may not be a truly entangled state, but a pseudo-entangled one: