Fig. 6: Density-density response function of NaH.

A \({{{\rm{Im}}}}\,{\chi }_{00}\) without RC. B \({{{\rm{Im}}}}\,{\chi }_{00}\) with RC. C \({{{\rm{Im}}}}\,{\chi }_{01}\) without RC. D \({{{\rm{Im}}}}\,{\chi }_{01}\) with RC. All experimental results are post-processed with McWeeny purification on the system-qubit states after constraining to the ancilla bitstring subspace. A broadening factor of η = 1.5 eV is used to generate the spectra. Without RC, the iToffoli decomposition yields qualitatively better results compared to the CZ decomposition. After RC is applied, the two decompositions yield comparable results.