Quantum Algorithms for the Study of Electronic Structure and Molecular Dynamics: Novel Computational Protocols

Graph-|Q⟩⟨C|: A Quantum Algorithm with Reduced Quantum Circuit Depth for Electronic Structure

“…Most efforts at computing electronic structure on quantum hardware are hindered by the depth of quantum circuits. ,,,,, Consequently, the complexity of the circuit, combined with limited gate fidelities on quantum hardware, leads to an enormous increase in error.…”

“…Orthogonally, the promise of solving exponentially hard problems using novel quantum hardware and quantum software is a rapidly evolving frontier. , Many quantum computing technologies, such as ion-traps, − superconducting coils, , Bosonic processors with photons, − solid-state devices and quantum dots inside cavities, − and Rydberg atoms − have emerged as potential computational platforms. In addition, algorithms to approximate electron correlation − for small molecules and quantum nuclear dynamics problems − have been implemented on quantum hardware devices.…”

“…Given these challenges, in Section we outline a hybrid quantum/classical algorithm based on a graph-theoretic decomposition of molecular structure to perform electron correlation calculations on an ensemble of quantum and classical hardware systems. The algorithm is also explained in detail in refs and and called “graph-| Q ⟩⟨ C |” and contains independent sets of classical and quantum algorithmic components within one umbrella. , In Section , we also show how graph-| Q ⟩⟨ C | can be used to provide a quantum algorithm for many-body expansions. In Section , we present our results from our quantum algorithm for medium-sized protonated and neutral water clusters.…”