  The production of quantum states required for use in quantum protocols &
technologies is studied by developing the tools to re-engineer a perfect state
transfer spin chain so that a separable input excitation is output over
multiple sites. We concentrate in particular on cases where the excitation is
superposed over a small subset of the qubits on the spin chain, known as
fractional revivals, demonstrating that spin chains are capable of producing a
far greater range of fractional revivals than previously known, at high speed.
We also provide a numerical technique for generating chains that produce
arbitrary single-excitation states, such as the W state.
