Resource-Efficient Simulation of Molecular Ground and Excited States Based on Contextual Subspace and Quantum Subspace Expansion.
Predicting spectra and photochemical pathways relies on the computation of molecular excited states. However, the practicality of near-term variational quantum algorithms is threatened by the prohibitive growth of measurement overheads. Integrating Quantum Subspace Expansion with the Contextual Subspace (CS) method, we...