• DOI:10.1103/PhysRevLett.100.050502
• Corpus ID: 24446837

Quantum discord and the power of one qubit.

@article{Datta2008QuantumDA,
  title={Quantum discord and the power of one qubit.},
  author={Animesh Datta and Anil Shaji and Carlton M. Caves},
  journal={Physical review letters},
  year={2008},
  volume={100 5},
  pages={
          050502
        }
}

• A. Datta, Anil Shaji, C. Caves
• Published 4 September 2007
• Physics
• Physical review letters

We use quantum discord to characterize the correlations present in the model called deterministic quantum computation with one quantum bit (DQC1), introduced by Knill and Laflamme [Phys. Rev. Lett. 81, 5672 (1998)10.1103/PhysRevLett.81.5672]. The model involves a collection of qubits in the completely mixed state coupled to a single control qubit that has nonzero purity. The initial state, operations, and measurements in the model all point to a natural bipartite split between the control qubit and the mixed ones. Although there is no entanglement between these two parts, we show that the quantum discord across this split is nonzero for typical instances of the DQC1 ciruit. Nonzero values of discord indicate the presence of nonclassical correlations. We propose quantum discord as figure of merit for characterizing the resources present in this computational model.