Quantum Computing Simulations Elucidate Active Spaces and Energetics of Amide Bond Detailing the Cis ‐ TS ‐ Trans Isomerization

ABSTRACT Quantum chemistry is among the most promising areas for quantum computing. In this study, we explored the efficacy of hybrid classical‐quantum algorithms in modeling peptide bond dynamics by analyzing the cis‐trans isomerization pathway, including an associated transition state. Three different active spaces were validated by coupled cluster calculations and the Qubit Efficient Encoding technique was applied to the chosen active spaces of the amide bond. Energy differences of the cis , trans and an isomerization transition state of the smallest suitable peptide models ( N ‐methylacetamide and H‐Gly‐Gly‐OH) were determined by the VQE method using 3 different hardware efficient ansätze (HEA). The VQE results from different combinations of active spaces and HEAs were compared with the exact results, and their difference converged to 0 kJ·mol −1 as the number of the layers of the ansätze increased and showed that in these cases VQE is applicable to calculate local energetic properties of amides.