Computing Coherence Vectors and Correlation Matrices with Application to Quantum Discord Quantification

Figure 1

The points are the values of the ameliorated Hilbert-Schmidt quantum discord of Werner states computed numerically using (32). The lines are the corresponding values of the AHSD plotted via the analytical formula: . Due to the symmetry of , here . In the inset the difference between the times taken by the two methods to compute the AHSD for a fixed value of is shown. We see clearly here that our optimized algorithm gives an exponential speedup against the brute force calculation of Bloch’s vectors and correlation matrix.