Symmetry Configuration Mapping for Compact Representation of Quantum Chemistry on Quantum Computers
Sean A. Fischer, Daniel Gunlycke · 2019
Near-term quantum computers may be able to significantly speed up complex computational tasks, but algorithms that make efficient use of quantum resources are needed. Quantum chemistry is widely regarded as a candidate for the first demonstration of quantum advantage with near-term quantum computers. In the present work, we demonstrate how taking advantage of the symmetries of a molecule leads to a reduction in the number of qubits required. This reduction in qubits also leads to a reduction in the number of variational parameters needed to reach chemical accuracy. Furthermore, we show how a simple modification of the hardware-efficient ansatz for the variational quantum eigensolver yields a factor of 3 reduction in the number of parameters with no loss in accuracy for most problems in quantum chemistry.