Abstract:

We propose a method for single spin measurement.  Our method uses techniques from the theory of quantum cellular automata to correlate a huge amount of ancillary spins to the one to be measured.  It has the distinct advantage of being very efficient, and to a certain extent fault-tolerant.  Under ideal conditions, it requires the application of only $O(\sqrt[3]{N})$ external radio frequency 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 extensive numerical simulation.

This is joint work with Michele Mosca (UW),  Paola Cappellaro (MIT),  and David G. Cory (MIT).