Spin amplifier for single spin measurement [chapter]

Paola Cappellaro, Joseph Emerson, Nicolas Boulant, Chandrasekhar Ramanathan, Seth Lloyd, David G. Cory
Quantum Computing in Solid State Systems  
We describe a new approach to the measurement of the state of a collapsed single spin by using many entangled spins as an amplifier. A single target spin is coupled via the natural dipolar Hamiltonian to a large collection of spins. Applying external radio frequency (r.f.) pulses, we can control the evolution of the system so that the ensemble spins reach one of two orthogonal states whose collective properties differ depending on the state of the target spin and are easily measured. We report
more » ... easured. We report the result of an experiment simulating this method on an ensemble liquid state NMR Quantum Processor. We suggest therefore that entanglement assisted metrology is compatible with the real control we have over physical spins, since the measurement process can actually be described in terms of the physical Hamiltonian of the spin system. By building on this work, and with the needed technical advances, it should be possible to detect a single nuclear spin.
doi:10.1007/0-387-31143-2_37 fatcat:5w4gmnieprc7ldlk2ueo45xliu