  We propose an approach for single spin measurement. Our method uses
techniques from the theory of quantum cellular automata to correlate a large
amount of ancillary spins to the one to be measured. It has the distinct
advantage of being efficient, and to a certain extent fault-tolerant. Under
ideal conditions, it requires the application of only order of cube root of N
steps (each requiring a constant number of rf pulses) to create a system of N
correlated spins. It is also fairly robust against pulse errors, imperfect
initial polarization of the ancilla spin system, and does not rely on
entanglement. We study the scalability of our scheme through numerical
simulation.
