Fig. 4
From: Measuring correlation and entanglement between molecular orbitals on a trapped-ion quantum computer
Orbital entropies and mutual informations obtained from the Quantinuum H1 trapped-ion quantum computer for image 1 and image 8 of the NEB reaction path in which the CASSCF wavefunction corresponds to the \(\langle S^2 \rangle = 2\) triplet. Superselection rules are applied to both images. Single orbital entropies, \(s1_i\), two orbital entropies, \(s2_{i,j}\), and mutual information, \(I_{i,j}\) are plotted for each molecular orbital or pair of orbitals for (a) image 1 and (b) image 8. In each plot ideal values (obtained from statevector simulations) are plotted along with the experimentally measured values, both with and without noise reduction. Error bars are obtained by bootstrap resampling the measurement shots 1000 times. Mutual information values are visualized as edges on a graph where the nodes are the four molecular orbitals for (c) image 1 and (d) image 8. Values are shown over many orders of magnitude by indicating the exponent through the color of the edge and the mantissa with its thickness. In (c) and (d) any negative values are excluded and only positive values are displayed.
