One-Step Implementation of Single Spin Measurement in Spin Star Network

We present an efficient one-step scheme for a single spin measurement based on nuclear magnetic resonance (NMR) techniques. This scheme considerably reduces the time of operation using a spin star network where a target spin and an ancillary spin are coupled to a ring of N spins. As opposed to the proposal in Phys. Rev. Lett. 97(2006)100501] using a cubic lattice crystal to achieve a cubic speedup, the distinct advantage of this scheme is that under ideal conditions it requires the application of only one step to create a system of N correlated spins. In the process of single spin measurement, the total macroscopic magnetization, the individual magnetization and the transfer fidelity are calculated analytically as simple cosine functions of time and the amplitude of irradiation.