Quantum-memory-assisted entropic uncertainty relation with a single   nitrogen-vacancy center in diamond
  The limitation of simultaneous measurements of noncommuting observables can be eliminated when the measured particle is maximally entangled with a quantum memory. We present a proposal for testing this quantum-memory-assisted entropic uncertainty relation in a single nitrogen-vacancy (N-V) center in diamond only by local electronic measurements. As an application, this entropic uncertainty relation is used to witness entanglement between the electron and nuclear spins of the N-V center, which is close to the reach of currently available technology. 
Z. Y. Xu, S. Q. Zhu, W. L. Yang
quant-ph