Experimentally Witnessing the Quantumness of Correlations

TL;DR

This paper demonstrates a simple, room-temperature NMR experiment that directly witnesses quantum correlations without complex calculations, aligning well with quantum discord measurements.

Contribution

It introduces an experimentally feasible witness for quantum correlations that requires only a few local measurements, avoiding extensive numerical optimization.

Findings

Successful experimental implementation of the witness in NMR system

Good agreement between witness results and quantum discord measurements

Efficient detection of quantum correlations with minimal measurements

Abstract

The quantification of quantum correlations (other than entanglement) usually entails laboured numerical optimization procedures also demanding quantum state tomographic methods. Thus it is interesting to have a laboratory friendly witness for the nature of correlations. In this Letter we report a direct experimental implementation of such a witness in a room temperature nuclear magnetic resonance system. In our experiment the nature of correlations is revealed by performing only few local magnetization measurements. We also compare the witness results with those for the symmetric quantum discord and we obtained a fairly good agreement.