@PRL Witnessing the quantumness of correlations in NMR

The quantification of quantum correlations (other than entanglement) usually entails labored numerical optimization procedures also demanding quantum state tomographic methods. Thus it is interesting to have a laboratory friendly witness for the nature of correlations. We report recently a direct experimental implementation of such a witness in a room temperature nuclear magnetic resonance (NMR) system. In our experiment the nature of correlations is revealed by performing only few local magnetization measurements.

For more information see: Phys. Rev. Lett. 107, 070501 (2011) | arXiv |

See also the optical implementation of the witness in: Phys. Rev. Lett. 108, 063601 (2012)

Coverage in the popular media:

PhysOrg: Quantum correlations without entanglement

Agência FAPESP: Medida da discórdia (quântica) | The new wave of qubits

Ciência Hoje: A medida da discórdia