Measuring bipartite quantum correlations of an unknown state
arXiv:1212.4262 · doi:10.1103/PhysRevLett.110.140501
Abstract
We report the experimental measurement of bipartite quantum correlations of an unknown two-qubit state. Using a liquid state Nuclear Magnetic Resonance (NMR) setup and employing geometric discord, we evaluate the quantum correlations of a state without resorting to prior knowledge of its density matrix. The method is applicable to any (2 x d) system and provides, in terms of number of measurements required, an advantage over full state tomography scaling with the dimension d of the unmeasured subsystem. The negativity of quantumness is measured as well for reference. We also observe the phenomenon of sudden transition of quantum correlations when local phase and amplitude damping channels are applied to the state.
5+2 pages, 3+1 figures. Published in PRL
References in corpus (12)
- Necessary and sufficient condition for non-zero quantum discord
- Experimental quantum computing without entanglement
- Robustness of quantum discord to sudden death
- Classical and quantum correlations under decoherence
- Interpreting quantum discord through quantum state merging
- Operational interpretations of quantum discord
- Linking Quantum Discord to Entanglement in a Measurement
- All non-classical correlations can be activated into distillable entanglement
- Experimentally Witnessing the Quantumness of Correlations
- Thermal Equilibrium as an Initial State for Quantum Computation by NMR
- Quantum discord in nuclear magnetic resonance systems at room temperature
- Theoretical insights on measuring quantum correlations