Sensing distant nuclear spins with a single electron spin
  We experimentally demonstrate the use of a single electronic spin to measure the quantum dynamics of distant individual nuclear spins from within a surrounding spin bath. Our technique exploits coherent control of the electron spin, allowing us to isolate and monitor nuclear spins weakly coupled to the electron spin. Specifically, we detect the evolution of distant individual carbon-13 nuclear spins coupled to single nitrogen vacancy centers in a diamond lattice with hyperfine couplings down to a factor of 8 below the electronic spin bare dephasing rate. Potential applications to nanoscale magnetic resonance imaging and quantum information processing are discussed. 
Shimon Kolkowitz, Quirin P. Unterreithmeier, Steven D. Bennett,   Mikhail D. Lukin
cond-mat.mes-hall quant-ph